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 Exception;
  29 use LockManager;
  30 use FSLockManager;
  31 use InvalidArgumentException;
  32 use RuntimeException;
  33 use stdClass;
  34
  35 /**
  36  * @ingroup Database
  37  */
  38 class DatabaseSqlite extends Database {
  39         /** @var bool Whether full text is enabled */
  40         private static $fulltextEnabled = null;
  41
  42         /** @var string Directory */
  43         protected $dbDir;
  44         /** @var string File name for SQLite database file */
  45         protected $dbPath;
  46         /** @var string Transaction mode */
  47         protected $trxMode;
  48
  49         /** @var int The number of rows affected as an integer */
  50         protected $lastAffectedRowCount;
  51         /** @var resource */
  52         protected $lastResultHandle;
  53
  54         /** @var PDO */
  55         protected $conn;
  56
  57         /** @var FSLockManager (hopefully on the same server as the DB) */
  58         protected $lockMgr;
  59
  60         /** @var array List of shared database already attached to this connection */
  61         private $alreadyAttached = [];
  62
  63         /**
  64          * Additional params include:
  65          *   - dbDirectory : directory containing the DB and the lock file directory
  66          *                   [defaults to $wgSQLiteDataDir]
  67          *   - dbFilePath  : use this to force the path of the DB file
  68          *   - trxMode     : one of (deferred, immediate, exclusive)
  69          * @param array $p
  70          */
  71         function __construct( array $p ) {
  72                 if ( isset( $p['dbFilePath'] ) ) {
  73                         $this->dbPath = $p['dbFilePath'];
  74                         $lockDomain = md5( $this->dbPath );
  75                         // Use "X" for things like X.sqlite and ":memory:" for RAM-only DBs
  76                         if ( !isset( $p['dbname'] ) || !strlen( $p['dbname'] ) ) {
  77                                 $p['dbname'] = preg_replace( '/\.sqlite\d?$/', '', basename( $this->dbPath ) );
  78                         }
  79                 } elseif ( isset( $p['dbDirectory'] ) ) {
  80                         $this->dbDir = $p['dbDirectory'];
  81                         $lockDomain = $p['dbname'];
  82                 } else {
  83                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
  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                         $this->queryLogger->warning( "Invalid SQLite transaction mode provided." );
  92                 }
  93
  94                 $this->lockMgr = new FSLockManager( [
  95                         'domain' => $lockDomain,
  96                         'lockDirectory' => "{$this->dbDir}/locks"
  97                 ] );
  98
  99                 parent::__construct( $p );
 100         }
 101
 102         protected static function getAttributes() {
 103                 return [ self::ATTR_DB_LEVEL_LOCKING => true ];
 104         }
 105
 106         /**
 107          * @param string $filename
 108          * @param array $p Options map; supports:
 109          *   - flags       : (same as __construct counterpart)
 110          *   - trxMode     : (same as __construct counterpart)
 111          *   - dbDirectory : (same as __construct counterpart)
 112          * @return DatabaseSqlite
 113          * @since 1.25
 114          */
 115         public static function newStandaloneInstance( $filename, array $p = [] ) {
 116                 $p['dbFilePath'] = $filename;
 117                 $p['schema'] = null;
 118                 $p['tablePrefix'] = '';
 119                 /** @var DatabaseSqlite $db */
 120                 $db = Database::factory( 'sqlite', $p );
 121
 122                 return $db;
 123         }
 124
 125         protected function doInitConnection() {
 126                 if ( $this->dbPath !== null ) {
 127                         // Standalone .sqlite file mode.
 128                         $this->openFile(
 129                                 $this->dbPath,
 130                                 $this->connectionParams['dbname'],
 131                                 $this->connectionParams['tablePrefix']
 132                         );
 133                 } elseif ( $this->dbDir !== null ) {
 134                         // Stock wiki mode using standard file names per DB
 135                         if ( strlen( $this->connectionParams['dbname'] ) ) {
 136                                 $this->open(
 137                                         $this->connectionParams['host'],
 138                                         $this->connectionParams['user'],
 139                                         $this->connectionParams['password'],
 140                                         $this->connectionParams['dbname'],
 141                                         $this->connectionParams['schema'],
 142                                         $this->connectionParams['tablePrefix']
 143                                 );
 144                         } else {
 145                                 // Caller will manually call open() later?
 146                                 $this->connLogger->debug( __METHOD__ . ': no database opened.' );
 147                         }
 148                 } else {
 149                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
 150                 }
 151         }
 152
 153         /**
 154          * @return string
 155          */
 156         function getType() {
 157                 return 'sqlite';
 158         }
 159
 160         /**
 161          * @todo Check if it should be true like parent class
 162          *
 163          * @return bool
 164          */
 165         function implicitGroupby() {
 166                 return false;
 167         }
 168
 169         protected function open( $server, $user, $pass, $dbName, $schema, $tablePrefix ) {
 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                 // Only $dbName is used, the other parameters are irrelevant for SQLite databases
 177                 $this->openFile( $fileName, $dbName, $tablePrefix );
 178
 179                 return (bool)$this->conn;
 180         }
 181
 182         /**
 183          * Opens a database file
 184          *
 185          * @param string $fileName
 186          * @param string $dbName
 187          * @param string $tablePrefix
 188          * @throws DBConnectionError
 189          * @return PDO|bool SQL connection or false if failed
 190          */
 191         protected function openFile( $fileName, $dbName, $tablePrefix ) {
 192                 $err = false;
 193
 194                 $this->dbPath = $fileName;
 195                 try {
 196                         if ( $this->flags & self::DBO_PERSISTENT ) {
 197                                 $this->conn = new PDO( "sqlite:$fileName", '', '',
 198                                         [ PDO::ATTR_PERSISTENT => true ] );
 199                         } else {
 200                                 $this->conn = new PDO( "sqlite:$fileName", '', '' );
 201                         }
 202                 } catch ( PDOException $e ) {
 203                         $err = $e->getMessage();
 204                 }
 205
 206                 if ( !$this->conn ) {
 207                         $this->queryLogger->debug( "DB connection error: $err\n" );
 208                         throw new DBConnectionError( $this, $err );
 209                 }
 210
 211                 $this->opened = is_object( $this->conn );
 212                 if ( $this->opened ) {
 213                         $this->currentDomain = new DatabaseDomain( $dbName, null, $tablePrefix );
 214                         # Set error codes only, don't raise exceptions
 215                         $this->conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 216                         # Enforce LIKE to be case sensitive, just like MySQL
 217                         $this->query( 'PRAGMA case_sensitive_like = 1' );
 218
 219                         return $this->conn;
 220                 }
 221
 222                 return false;
 223         }
 224
 225         /**
 226          * @return string SQLite DB file path
 227          * @since 1.25
 228          */
 229         public function getDbFilePath() {
 230                 return $this->dbPath;
 231         }
 232
 233         /**
 234          * Does not actually close the connection, just destroys the reference for GC to do its work
 235          * @return bool
 236          */
 237         protected function closeConnection() {
 238                 $this->conn = null;
 239
 240                 return true;
 241         }
 242
 243         /**
 244          * Generates a database file name. Explicitly public for installer.
 245          * @param string $dir Directory where database resides
 246          * @param string $dbName Database name
 247          * @return string
 248          */
 249         public static function generateFileName( $dir, $dbName ) {
 250                 return "$dir/$dbName.sqlite";
 251         }
 252
 253         /**
 254          * Check if the searchindext table is FTS enabled.
 255          * @return bool False if not enabled.
 256          */
 257         function checkForEnabledSearch() {
 258                 if ( self::$fulltextEnabled === null ) {
 259                         self::$fulltextEnabled = false;
 260                         $table = $this->tableName( 'searchindex' );
 261                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 262                         if ( $res ) {
 263                                 $row = $res->fetchRow();
 264                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 265                         }
 266                 }
 267
 268                 return self::$fulltextEnabled;
 269         }
 270
 271         /**
 272          * Returns version of currently supported SQLite fulltext search module or false if none present.
 273          * @return string
 274          */
 275         static function getFulltextSearchModule() {
 276                 static $cachedResult = null;
 277                 if ( $cachedResult !== null ) {
 278                         return $cachedResult;
 279                 }
 280                 $cachedResult = false;
 281                 $table = 'dummy_search_test';
 282
 283                 $db = self::newStandaloneInstance( ':memory:' );
 284                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 285                         $cachedResult = 'FTS3';
 286                 }
 287                 $db->close();
 288
 289                 return $cachedResult;
 290         }
 291
 292         /**
 293          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 294          * for details.
 295          *
 296          * @param string $name Database name to be used in queries like
 297          *   SELECT foo FROM dbname.table
 298          * @param bool|string $file Database file name. If omitted, will be generated
 299          *   using $name and configured data directory
 300          * @param string $fname Calling function name
 301          * @return ResultWrapper
 302          */
 303         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 304                 if ( !$file ) {
 305                         $file = self::generateFileName( $this->dbDir, $name );
 306                 }
 307                 $file = $this->addQuotes( $file );
 308
 309                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 310         }
 311
 312         protected function isWriteQuery( $sql ) {
 313                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 314         }
 315
 316         protected function isTransactableQuery( $sql ) {
 317                 return parent::isTransactableQuery( $sql ) && !in_array(
 318                         $this->getQueryVerb( $sql ),
 319                         [ 'ATTACH', 'PRAGMA' ],
 320                         true
 321                 );
 322         }
 323
 324         /**
 325          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 326          *
 327          * @param string $sql
 328          * @return bool|ResultWrapper
 329          */
 330         protected function doQuery( $sql ) {
 331                 $res = $this->getBindingHandle()->query( $sql );
 332                 if ( $res === false ) {
 333                         return false;
 334                 }
 335
 336                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 337                 $this->lastAffectedRowCount = $r->rowCount();
 338                 $res = new ResultWrapper( $this, $r->fetchAll() );
 339
 340                 return $res;
 341         }
 342
 343         /**
 344          * @param ResultWrapper|mixed $res
 345          */
 346         function freeResult( $res ) {
 347                 if ( $res instanceof ResultWrapper ) {
 348                         $res->result = null;
 349                 } else {
 350                         $res = null;
 351                 }
 352         }
 353
 354         /**
 355          * @param ResultWrapper|array $res
 356          * @return stdClass|bool
 357          */
 358         function fetchObject( $res ) {
 359                 if ( $res instanceof ResultWrapper ) {
 360                         $r =& $res->result;
 361                 } else {
 362                         $r =& $res;
 363                 }
 364
 365                 $cur = current( $r );
 366                 if ( is_array( $cur ) ) {
 367                         next( $r );
 368                         $obj = new stdClass;
 369                         foreach ( $cur as $k => $v ) {
 370                                 if ( !is_numeric( $k ) ) {
 371                                         $obj->$k = $v;
 372                                 }
 373                         }
 374
 375                         return $obj;
 376                 }
 377
 378                 return false;
 379         }
 380
 381         /**
 382          * @param ResultWrapper|mixed $res
 383          * @return array|bool
 384          */
 385         function fetchRow( $res ) {
 386                 if ( $res instanceof ResultWrapper ) {
 387                         $r =& $res->result;
 388                 } else {
 389                         $r =& $res;
 390                 }
 391                 $cur = current( $r );
 392                 if ( is_array( $cur ) ) {
 393                         next( $r );
 394
 395                         return $cur;
 396                 }
 397
 398                 return false;
 399         }
 400
 401         /**
 402          * The PDO::Statement class implements the array interface so count() will work
 403          *
 404          * @param ResultWrapper|array|false $res
 405          * @return int
 406          */
 407         function numRows( $res ) {
 408                 // false does not implement Countable
 409                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 410
 411                 return is_array( $r ) ? count( $r ) : 0;
 412         }
 413
 414         /**
 415          * @param ResultWrapper $res
 416          * @return int
 417          */
 418         function numFields( $res ) {
 419                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 420                 if ( is_array( $r ) && count( $r ) > 0 ) {
 421                         // The size of the result array is twice the number of fields. (T67578)
 422                         return count( $r[0] ) / 2;
 423                 } else {
 424                         // If the result is empty return 0
 425                         return 0;
 426                 }
 427         }
 428
 429         /**
 430          * @param ResultWrapper $res
 431          * @param int $n
 432          * @return bool
 433          */
 434         function fieldName( $res, $n ) {
 435                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 436                 if ( is_array( $r ) ) {
 437                         $keys = array_keys( $r[0] );
 438
 439                         return $keys[$n];
 440                 }
 441
 442                 return false;
 443         }
 444
 445         /**
 446          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 447          *
 448          * @param string $name
 449          * @param string $format
 450          * @return string
 451          */
 452         function tableName( $name, $format = 'quoted' ) {
 453                 // table names starting with sqlite_ are reserved
 454                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 455                         return $name;
 456                 }
 457
 458                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 459         }
 460
 461         /**
 462          * This must be called after nextSequenceVal
 463          *
 464          * @return int
 465          */
 466         function insertId() {
 467                 // PDO::lastInsertId yields a string :(
 468                 return intval( $this->getBindingHandle()->lastInsertId() );
 469         }
 470
 471         /**
 472          * @param ResultWrapper|array $res
 473          * @param int $row
 474          */
 475         function dataSeek( $res, $row ) {
 476                 if ( $res instanceof ResultWrapper ) {
 477                         $r =& $res->result;
 478                 } else {
 479                         $r =& $res;
 480                 }
 481                 reset( $r );
 482                 if ( $row > 0 ) {
 483                         for ( $i = 0; $i < $row; $i++ ) {
 484                                 next( $r );
 485                         }
 486                 }
 487         }
 488
 489         /**
 490          * @return string
 491          */
 492         function lastError() {
 493                 if ( !is_object( $this->conn ) ) {
 494                         return "Cannot return last error, no db connection";
 495                 }
 496                 $e = $this->conn->errorInfo();
 497
 498                 return $e[2] ?? '';
 499         }
 500
 501         /**
 502          * @return string
 503          */
 504         function lastErrno() {
 505                 if ( !is_object( $this->conn ) ) {
 506                         return "Cannot return last error, no db connection";
 507                 } else {
 508                         $info = $this->conn->errorInfo();
 509
 510                         return $info[1];
 511                 }
 512         }
 513
 514         /**
 515          * @return int
 516          */
 517         protected function fetchAffectedRowCount() {
 518                 return $this->lastAffectedRowCount;
 519         }
 520
 521         function tableExists( $table, $fname = __METHOD__ ) {
 522                 $tableRaw = $this->tableName( $table, 'raw' );
 523                 if ( isset( $this->sessionTempTables[$tableRaw] ) ) {
 524                         return true; // already known to exist
 525                 }
 526
 527                 $encTable = $this->addQuotes( $tableRaw );
 528                 $res = $this->query(
 529                         "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable" );
 530
 531                 return $res->numRows() ? true : false;
 532         }
 533
 534         /**
 535          * Returns information about an index
 536          * Returns false if the index does not exist
 537          * - if errors are explicitly ignored, returns NULL on failure
 538          *
 539          * @param string $table
 540          * @param string $index
 541          * @param string $fname
 542          * @return array|false
 543          */
 544         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 545                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 546                 $res = $this->query( $sql, $fname );
 547                 if ( !$res || $res->numRows() == 0 ) {
 548                         return false;
 549                 }
 550                 $info = [];
 551                 foreach ( $res as $row ) {
 552                         $info[] = $row->name;
 553                 }
 554
 555                 return $info;
 556         }
 557
 558         /**
 559          * @param string $table
 560          * @param string $index
 561          * @param string $fname
 562          * @return bool|null
 563          */
 564         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 565                 $row = $this->selectRow( 'sqlite_master', '*',
 566                         [
 567                                 'type' => 'index',
 568                                 'name' => $this->indexName( $index ),
 569                         ], $fname );
 570                 if ( !$row || !isset( $row->sql ) ) {
 571                         return null;
 572                 }
 573
 574                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 575                 $indexPos = strpos( $row->sql, 'INDEX' );
 576                 if ( $indexPos === false ) {
 577                         return null;
 578                 }
 579                 $firstPart = substr( $row->sql, 0, $indexPos );
 580                 $options = explode( ' ', $firstPart );
 581
 582                 return in_array( 'UNIQUE', $options );
 583         }
 584
 585         /**
 586          * Filter the options used in SELECT statements
 587          *
 588          * @param array $options
 589          * @return array
 590          */
 591         function makeSelectOptions( $options ) {
 592                 foreach ( $options as $k => $v ) {
 593                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 594                                 $options[$k] = '';
 595                         }
 596                 }
 597
 598                 return parent::makeSelectOptions( $options );
 599         }
 600
 601         /**
 602          * @param array $options
 603          * @return array
 604          */
 605         protected function makeUpdateOptionsArray( $options ) {
 606                 $options = parent::makeUpdateOptionsArray( $options );
 607                 $options = self::fixIgnore( $options );
 608
 609                 return $options;
 610         }
 611
 612         /**
 613          * @param array $options
 614          * @return array
 615          */
 616         static function fixIgnore( $options ) {
 617                 # SQLite uses OR IGNORE not just IGNORE
 618                 foreach ( $options as $k => $v ) {
 619                         if ( $v == 'IGNORE' ) {
 620                                 $options[$k] = 'OR IGNORE';
 621                         }
 622                 }
 623
 624                 return $options;
 625         }
 626
 627         /**
 628          * @param array $options
 629          * @return string
 630          */
 631         function makeInsertOptions( $options ) {
 632                 $options = self::fixIgnore( $options );
 633
 634                 return parent::makeInsertOptions( $options );
 635         }
 636
 637         /**
 638          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 639          * @param string $table
 640          * @param array $a
 641          * @param string $fname
 642          * @param array $options
 643          * @return bool
 644          */
 645         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 646                 if ( !count( $a ) ) {
 647                         return true;
 648                 }
 649
 650                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 651                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 652                         $affectedRowCount = 0;
 653                         try {
 654                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 655                                 foreach ( $a as $v ) {
 656                                         parent::insert( $table, $v, "$fname/multi-row", $options );
 657                                 }
 658                                 $this->endAtomic( $fname );
 659                         } catch ( Exception $e ) {
 660                                 $this->cancelAtomic( $fname );
 661                                 throw $e;
 662                         }
 663                         $this->affectedRowCount = $affectedRowCount;
 664                 } else {
 665                         parent::insert( $table, $a, "$fname/single-row", $options );
 666                 }
 667
 668                 return true;
 669         }
 670
 671         /**
 672          * @param string $table
 673          * @param array $uniqueIndexes Unused
 674          * @param string|array $rows
 675          * @param string $fname
 676          */
 677         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 678                 if ( !count( $rows ) ) {
 679                         return;
 680                 }
 681
 682                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 683                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 684                         $affectedRowCount = 0;
 685                         try {
 686                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 687                                 foreach ( $rows as $v ) {
 688                                         $this->nativeReplace( $table, $v, "$fname/multi-row" );
 689                                         $affectedRowCount += $this->affectedRows();
 690                                 }
 691                                 $this->endAtomic( $fname );
 692                         } catch ( Exception $e ) {
 693                                 $this->cancelAtomic( $fname );
 694                                 throw $e;
 695                         }
 696                         $this->affectedRowCount = $affectedRowCount;
 697                 } else {
 698                         $this->nativeReplace( $table, $rows, "$fname/single-row" );
 699                 }
 700         }
 701
 702         /**
 703          * Returns the size of a text field, or -1 for "unlimited"
 704          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 705          *
 706          * @param string $table
 707          * @param string $field
 708          * @return int
 709          */
 710         function textFieldSize( $table, $field ) {
 711                 return -1;
 712         }
 713
 714         /**
 715          * @return bool
 716          */
 717         function unionSupportsOrderAndLimit() {
 718                 return false;
 719         }
 720
 721         /**
 722          * @param string[] $sqls
 723          * @param bool $all Whether to "UNION ALL" or not
 724          * @return string
 725          */
 726         function unionQueries( $sqls, $all ) {
 727                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 728
 729                 return implode( $glue, $sqls );
 730         }
 731
 732         /**
 733          * @return bool
 734          */
 735         function wasDeadlock() {
 736                 return $this->lastErrno() == 5; // SQLITE_BUSY
 737         }
 738
 739         /**
 740          * @return bool
 741          */
 742         function wasReadOnlyError() {
 743                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 744         }
 745
 746         public function wasConnectionError( $errno ) {
 747                 return $errno == 17; // SQLITE_SCHEMA;
 748         }
 749
 750         protected function wasKnownStatementRollbackError() {
 751                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 752                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 753                 // https://sqlite.org/lang_createtable.html#uniqueconst
 754                 // https://sqlite.org/lang_conflict.html
 755                 return false;
 756         }
 757
 758         /**
 759          * @return string Wikitext of a link to the server software's web site
 760          */
 761         public function getSoftwareLink() {
 762                 return "[{{int:version-db-sqlite-url}} SQLite]";
 763         }
 764
 765         /**
 766          * @return string Version information from the database
 767          */
 768         function getServerVersion() {
 769                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 770
 771                 return $ver;
 772         }
 773
 774         /**
 775          * Get information about a given field
 776          * Returns false if the field does not exist.
 777          *
 778          * @param string $table
 779          * @param string $field
 780          * @return SQLiteField|bool False on failure
 781          */
 782         function fieldInfo( $table, $field ) {
 783                 $tableName = $this->tableName( $table );
 784                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 785                 $res = $this->query( $sql, __METHOD__ );
 786                 foreach ( $res as $row ) {
 787                         if ( $row->name == $field ) {
 788                                 return new SQLiteField( $row, $tableName );
 789                         }
 790                 }
 791
 792                 return false;
 793         }
 794
 795         protected function doBegin( $fname = '' ) {
 796                 if ( $this->trxMode ) {
 797                         $this->query( "BEGIN {$this->trxMode}", $fname );
 798                 } else {
 799                         $this->query( 'BEGIN', $fname );
 800                 }
 801                 $this->trxLevel = 1;
 802         }
 803
 804         /**
 805          * @param string $s
 806          * @return string
 807          */
 808         function strencode( $s ) {
 809                 return substr( $this->addQuotes( $s ), 1, -1 );
 810         }
 811
 812         /**
 813          * @param string $b
 814          * @return Blob
 815          */
 816         function encodeBlob( $b ) {
 817                 return new Blob( $b );
 818         }
 819
 820         /**
 821          * @param Blob|string $b
 822          * @return string
 823          */
 824         function decodeBlob( $b ) {
 825                 if ( $b instanceof Blob ) {
 826                         $b = $b->fetch();
 827                 }
 828
 829                 return $b;
 830         }
 831
 832         /**
 833          * @param string|int|null|bool|Blob $s
 834          * @return string|int
 835          */
 836         function addQuotes( $s ) {
 837                 if ( $s instanceof Blob ) {
 838                         return "x'" . bin2hex( $s->fetch() ) . "'";
 839                 } elseif ( is_bool( $s ) ) {
 840                         return (int)$s;
 841                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 842                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 843                         // This is a known limitation of SQLite's mprintf function which PDO
 844                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 845                         // https://bugs.php.net/bug.php?id=63419
 846                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 847                         // https://bugs.php.net/bug.php?id=62361
 848                         // There is an additional bug regarding sorting this data after insert
 849                         // on older versions of sqlite shipped with ubuntu 12.04
 850                         // https://phabricator.wikimedia.org/T74367
 851                         $this->queryLogger->debug(
 852                                 __FUNCTION__ .
 853                                 ': Quoting value containing null byte. ' .
 854                                 'For consistency all binary data should have been ' .
 855                                 'first processed with self::encodeBlob()'
 856                         );
 857                         return "x'" . bin2hex( (string)$s ) . "'";
 858                 } else {
 859                         return $this->getBindingHandle()->quote( (string)$s );
 860                 }
 861         }
 862
 863         public function buildSubstring( $input, $startPosition, $length = null ) {
 864                 $this->assertBuildSubstringParams( $startPosition, $length );
 865                 $params = [ $input, $startPosition ];
 866                 if ( $length !== null ) {
 867                         $params[] = $length;
 868                 }
 869                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 870         }
 871
 872         /**
 873          * @param string $field Field or column to cast
 874          * @return string
 875          * @since 1.28
 876          */
 877         public function buildStringCast( $field ) {
 878                 return 'CAST ( ' . $field . ' AS TEXT )';
 879         }
 880
 881         /**
 882          * No-op version of deadlockLoop
 883          *
 884          * @return mixed
 885          */
 886         public function deadlockLoop( /*...*/ ) {
 887                 $args = func_get_args();
 888                 $function = array_shift( $args );
 889
 890                 return $function( ...$args );
 891         }
 892
 893         /**
 894          * @param string $s
 895          * @return string
 896          */
 897         protected function replaceVars( $s ) {
 898                 $s = parent::replaceVars( $s );
 899                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 900                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 901
 902                         // binary/varbinary column type -> blob
 903                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 904                         // no such thing as unsigned
 905                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 906                         // INT -> INTEGER
 907                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 908                         // floating point types -> REAL
 909                         $s = preg_replace(
 910                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 911                                 'REAL',
 912                                 $s
 913                         );
 914                         // varchar -> TEXT
 915                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 916                         // TEXT normalization
 917                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 918                         // BLOB normalization
 919                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 920                         // BOOL -> INTEGER
 921                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 922                         // DATETIME -> TEXT
 923                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 924                         // No ENUM type
 925                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 926                         // binary collation type -> nothing
 927                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 928                         // auto_increment -> autoincrement
 929                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 930                         // No explicit options
 931                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 932                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 933                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 934                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 935                         // No truncated indexes
 936                         $s = preg_replace( '/\(\d+\)/', '', $s );
 937                         // No FULLTEXT
 938                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 939                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 940                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 941                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 942                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 943                         // INSERT IGNORE --> INSERT OR IGNORE
 944                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 945                 }
 946
 947                 return $s;
 948         }
 949
 950         public function lock( $lockName, $method, $timeout = 5 ) {
 951                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 952                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 953                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 954                         }
 955                 }
 956
 957                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 958         }
 959
 960         public function unlock( $lockName, $method ) {
 961                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 962         }
 963
 964         /**
 965          * Build a concatenation list to feed into a SQL query
 966          *
 967          * @param string[] $stringList
 968          * @return string
 969          */
 970         function buildConcat( $stringList ) {
 971                 return '(' . implode( ') || (', $stringList ) . ')';
 972         }
 973
 974         public function buildGroupConcatField(
 975                 $delim, $table, $field, $conds = '', $join_conds = []
 976         ) {
 977                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 978
 979                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 980         }
 981
 982         /**
 983          * @param string $oldName
 984          * @param string $newName
 985          * @param bool $temporary
 986          * @param string $fname
 987          * @return bool|ResultWrapper
 988          * @throws RuntimeException
 989          */
 990         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 991                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 992                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 993                 $obj = $this->fetchObject( $res );
 994                 if ( !$obj ) {
 995                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
 996                 }
 997                 $sql = $obj->sql;
 998                 $sql = preg_replace(
 999                         '/(?<=\W)"?' .
1000                                 preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
1001                                 '"?(?=\W)/',
1002                         $this->addIdentifierQuotes( $newName ),
1003                         $sql,
1004                         1
1005                 );
1006                 if ( $temporary ) {
1007                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
1008                                 $this->queryLogger->debug(
1009                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
1010                         } else {
1011                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
1012                         }
1013                 }
1014
1015                 $res = $this->query( $sql, $fname );
1016
1017                 // Take over indexes
1018                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
1019                 foreach ( $indexList as $index ) {
1020                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
1021                                 continue;
1022                         }
1023
1024                         if ( $index->unique ) {
1025                                 $sql = 'CREATE UNIQUE INDEX';
1026                         } else {
1027                                 $sql = 'CREATE INDEX';
1028                         }
1029                         // Try to come up with a new index name, given indexes have database scope in SQLite
1030                         $indexName = $newName . '_' . $index->name;
1031                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1032
1033                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1034                         $fields = [];
1035                         foreach ( $indexInfo as $indexInfoRow ) {
1036                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1037                         }
1038
1039                         $sql .= '(' . implode( ',', $fields ) . ')';
1040
1041                         $this->query( $sql );
1042                 }
1043
1044                 return $res;
1045         }
1046
1047         /**
1048          * List all tables on the database
1049          *
1050          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1051          * @param string $fname Calling function name
1052          *
1053          * @return array
1054          */
1055         function listTables( $prefix = null, $fname = __METHOD__ ) {
1056                 $result = $this->select(
1057                         'sqlite_master',
1058                         'name',
1059                         "type='table'"
1060                 );
1061
1062                 $endArray = [];
1063
1064                 foreach ( $result as $table ) {
1065                         $vars = get_object_vars( $table );
1066                         $table = array_pop( $vars );
1067
1068                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1069                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1070                                         $endArray[] = $table;
1071                                 }
1072                         }
1073                 }
1074
1075                 return $endArray;
1076         }
1077
1078         /**
1079          * Override due to no CASCADE support
1080          *
1081          * @param string $tableName
1082          * @param string $fName
1083          * @return bool|ResultWrapper
1084          * @throws DBReadOnlyError
1085          */
1086         public function dropTable( $tableName, $fName = __METHOD__ ) {
1087                 if ( !$this->tableExists( $tableName, $fName ) ) {
1088                         return false;
1089                 }
1090                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1091
1092                 return $this->query( $sql, $fName );
1093         }
1094
1095         public function setTableAliases( array $aliases ) {
1096                 parent::setTableAliases( $aliases );
1097                 foreach ( $this->tableAliases as $params ) {
1098                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1099                                 continue;
1100                         }
1101                         $this->attachDatabase( $params['dbname'] );
1102                         $this->alreadyAttached[$params['dbname']] = true;
1103                 }
1104         }
1105
1106         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1107                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1108                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1109                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1110         }
1111
1112         public function databasesAreIndependent() {
1113                 return true;
1114         }
1115
1116         /**
1117          * @return string
1118          */
1119         public function __toString() {
1120                 return is_object( $this->conn )
1121                         ? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
1122                         : '(not connected)';
1123         }
1124
1125         /**
1126          * @return PDO
1127          */
1128         protected function getBindingHandle() {
1129                 return parent::getBindingHandle();
1130         }
1131 }
1132
1133 /**
1134  * @deprecated since 1.29
1135  */
1136 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );