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                         $sync = $this->sessionVars['synchronous'] ?? null;
 220                         if ( in_array( $sync, [ 'EXTRA', 'FULL', 'NORMAL' ], true ) ) {
 221                                 $this->query( "PRAGMA synchronous = $sync" );
 222                         }
 223
 224                         return $this->conn;
 225                 }
 226
 227                 return false;
 228         }
 229
 230         /**
 231          * @return string SQLite DB file path
 232          * @since 1.25
 233          */
 234         public function getDbFilePath() {
 235                 return $this->dbPath;
 236         }
 237
 238         /**
 239          * Does not actually close the connection, just destroys the reference for GC to do its work
 240          * @return bool
 241          */
 242         protected function closeConnection() {
 243                 $this->conn = null;
 244
 245                 return true;
 246         }
 247
 248         /**
 249          * Generates a database file name. Explicitly public for installer.
 250          * @param string $dir Directory where database resides
 251          * @param string $dbName Database name
 252          * @return string
 253          */
 254         public static function generateFileName( $dir, $dbName ) {
 255                 return "$dir/$dbName.sqlite";
 256         }
 257
 258         /**
 259          * Check if the searchindext table is FTS enabled.
 260          * @return bool False if not enabled.
 261          */
 262         function checkForEnabledSearch() {
 263                 if ( self::$fulltextEnabled === null ) {
 264                         self::$fulltextEnabled = false;
 265                         $table = $this->tableName( 'searchindex' );
 266                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 267                         if ( $res ) {
 268                                 $row = $res->fetchRow();
 269                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 270                         }
 271                 }
 272
 273                 return self::$fulltextEnabled;
 274         }
 275
 276         /**
 277          * Returns version of currently supported SQLite fulltext search module or false if none present.
 278          * @return string
 279          */
 280         static function getFulltextSearchModule() {
 281                 static $cachedResult = null;
 282                 if ( $cachedResult !== null ) {
 283                         return $cachedResult;
 284                 }
 285                 $cachedResult = false;
 286                 $table = 'dummy_search_test';
 287
 288                 $db = self::newStandaloneInstance( ':memory:' );
 289                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 290                         $cachedResult = 'FTS3';
 291                 }
 292                 $db->close();
 293
 294                 return $cachedResult;
 295         }
 296
 297         /**
 298          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 299          * for details.
 300          *
 301          * @param string $name Database name to be used in queries like
 302          *   SELECT foo FROM dbname.table
 303          * @param bool|string $file Database file name. If omitted, will be generated
 304          *   using $name and configured data directory
 305          * @param string $fname Calling function name
 306          * @return ResultWrapper
 307          */
 308         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 309                 if ( !$file ) {
 310                         $file = self::generateFileName( $this->dbDir, $name );
 311                 }
 312                 $file = $this->addQuotes( $file );
 313
 314                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 315         }
 316
 317         protected function isWriteQuery( $sql ) {
 318                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 319         }
 320
 321         protected function isTransactableQuery( $sql ) {
 322                 return parent::isTransactableQuery( $sql ) && !in_array(
 323                         $this->getQueryVerb( $sql ),
 324                         [ 'ATTACH', 'PRAGMA' ],
 325                         true
 326                 );
 327         }
 328
 329         /**
 330          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 331          *
 332          * @param string $sql
 333          * @return bool|ResultWrapper
 334          */
 335         protected function doQuery( $sql ) {
 336                 $res = $this->getBindingHandle()->query( $sql );
 337                 if ( $res === false ) {
 338                         return false;
 339                 }
 340
 341                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 342                 $this->lastAffectedRowCount = $r->rowCount();
 343                 $res = new ResultWrapper( $this, $r->fetchAll() );
 344
 345                 return $res;
 346         }
 347
 348         /**
 349          * @param ResultWrapper|mixed $res
 350          */
 351         function freeResult( $res ) {
 352                 if ( $res instanceof ResultWrapper ) {
 353                         $res->result = null;
 354                 } else {
 355                         $res = null;
 356                 }
 357         }
 358
 359         /**
 360          * @param ResultWrapper|array $res
 361          * @return stdClass|bool
 362          */
 363         function fetchObject( $res ) {
 364                 if ( $res instanceof ResultWrapper ) {
 365                         $r =& $res->result;
 366                 } else {
 367                         $r =& $res;
 368                 }
 369
 370                 $cur = current( $r );
 371                 if ( is_array( $cur ) ) {
 372                         next( $r );
 373                         $obj = new stdClass;
 374                         foreach ( $cur as $k => $v ) {
 375                                 if ( !is_numeric( $k ) ) {
 376                                         $obj->$k = $v;
 377                                 }
 378                         }
 379
 380                         return $obj;
 381                 }
 382
 383                 return false;
 384         }
 385
 386         /**
 387          * @param ResultWrapper|mixed $res
 388          * @return array|bool
 389          */
 390         function fetchRow( $res ) {
 391                 if ( $res instanceof ResultWrapper ) {
 392                         $r =& $res->result;
 393                 } else {
 394                         $r =& $res;
 395                 }
 396                 $cur = current( $r );
 397                 if ( is_array( $cur ) ) {
 398                         next( $r );
 399
 400                         return $cur;
 401                 }
 402
 403                 return false;
 404         }
 405
 406         /**
 407          * The PDO::Statement class implements the array interface so count() will work
 408          *
 409          * @param ResultWrapper|array|false $res
 410          * @return int
 411          */
 412         function numRows( $res ) {
 413                 // false does not implement Countable
 414                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 415
 416                 return is_array( $r ) ? count( $r ) : 0;
 417         }
 418
 419         /**
 420          * @param ResultWrapper $res
 421          * @return int
 422          */
 423         function numFields( $res ) {
 424                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 425                 if ( is_array( $r ) && count( $r ) > 0 ) {
 426                         // The size of the result array is twice the number of fields. (T67578)
 427                         return count( $r[0] ) / 2;
 428                 } else {
 429                         // If the result is empty return 0
 430                         return 0;
 431                 }
 432         }
 433
 434         /**
 435          * @param ResultWrapper $res
 436          * @param int $n
 437          * @return bool
 438          */
 439         function fieldName( $res, $n ) {
 440                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 441                 if ( is_array( $r ) ) {
 442                         $keys = array_keys( $r[0] );
 443
 444                         return $keys[$n];
 445                 }
 446
 447                 return false;
 448         }
 449
 450         /**
 451          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 452          *
 453          * @param string $name
 454          * @param string $format
 455          * @return string
 456          */
 457         function tableName( $name, $format = 'quoted' ) {
 458                 // table names starting with sqlite_ are reserved
 459                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 460                         return $name;
 461                 }
 462
 463                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 464         }
 465
 466         /**
 467          * This must be called after nextSequenceVal
 468          *
 469          * @return int
 470          */
 471         function insertId() {
 472                 // PDO::lastInsertId yields a string :(
 473                 return intval( $this->getBindingHandle()->lastInsertId() );
 474         }
 475
 476         /**
 477          * @param ResultWrapper|array $res
 478          * @param int $row
 479          */
 480         function dataSeek( $res, $row ) {
 481                 if ( $res instanceof ResultWrapper ) {
 482                         $r =& $res->result;
 483                 } else {
 484                         $r =& $res;
 485                 }
 486                 reset( $r );
 487                 if ( $row > 0 ) {
 488                         for ( $i = 0; $i < $row; $i++ ) {
 489                                 next( $r );
 490                         }
 491                 }
 492         }
 493
 494         /**
 495          * @return string
 496          */
 497         function lastError() {
 498                 if ( !is_object( $this->conn ) ) {
 499                         return "Cannot return last error, no db connection";
 500                 }
 501                 $e = $this->conn->errorInfo();
 502
 503                 return $e[2] ?? '';
 504         }
 505
 506         /**
 507          * @return string
 508          */
 509         function lastErrno() {
 510                 if ( !is_object( $this->conn ) ) {
 511                         return "Cannot return last error, no db connection";
 512                 } else {
 513                         $info = $this->conn->errorInfo();
 514
 515                         return $info[1];
 516                 }
 517         }
 518
 519         /**
 520          * @return int
 521          */
 522         protected function fetchAffectedRowCount() {
 523                 return $this->lastAffectedRowCount;
 524         }
 525
 526         function tableExists( $table, $fname = __METHOD__ ) {
 527                 $tableRaw = $this->tableName( $table, 'raw' );
 528                 if ( isset( $this->sessionTempTables[$tableRaw] ) ) {
 529                         return true; // already known to exist
 530                 }
 531
 532                 $encTable = $this->addQuotes( $tableRaw );
 533                 $res = $this->query(
 534                         "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable" );
 535
 536                 return $res->numRows() ? true : false;
 537         }
 538
 539         /**
 540          * Returns information about an index
 541          * Returns false if the index does not exist
 542          * - if errors are explicitly ignored, returns NULL on failure
 543          *
 544          * @param string $table
 545          * @param string $index
 546          * @param string $fname
 547          * @return array|false
 548          */
 549         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 550                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 551                 $res = $this->query( $sql, $fname );
 552                 if ( !$res || $res->numRows() == 0 ) {
 553                         return false;
 554                 }
 555                 $info = [];
 556                 foreach ( $res as $row ) {
 557                         $info[] = $row->name;
 558                 }
 559
 560                 return $info;
 561         }
 562
 563         /**
 564          * @param string $table
 565          * @param string $index
 566          * @param string $fname
 567          * @return bool|null
 568          */
 569         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 570                 $row = $this->selectRow( 'sqlite_master', '*',
 571                         [
 572                                 'type' => 'index',
 573                                 'name' => $this->indexName( $index ),
 574                         ], $fname );
 575                 if ( !$row || !isset( $row->sql ) ) {
 576                         return null;
 577                 }
 578
 579                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 580                 $indexPos = strpos( $row->sql, 'INDEX' );
 581                 if ( $indexPos === false ) {
 582                         return null;
 583                 }
 584                 $firstPart = substr( $row->sql, 0, $indexPos );
 585                 $options = explode( ' ', $firstPart );
 586
 587                 return in_array( 'UNIQUE', $options );
 588         }
 589
 590         /**
 591          * Filter the options used in SELECT statements
 592          *
 593          * @param array $options
 594          * @return array
 595          */
 596         function makeSelectOptions( $options ) {
 597                 foreach ( $options as $k => $v ) {
 598                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 599                                 $options[$k] = '';
 600                         }
 601                 }
 602
 603                 return parent::makeSelectOptions( $options );
 604         }
 605
 606         /**
 607          * @param array $options
 608          * @return array
 609          */
 610         protected function makeUpdateOptionsArray( $options ) {
 611                 $options = parent::makeUpdateOptionsArray( $options );
 612                 $options = self::fixIgnore( $options );
 613
 614                 return $options;
 615         }
 616
 617         /**
 618          * @param array $options
 619          * @return array
 620          */
 621         static function fixIgnore( $options ) {
 622                 # SQLite uses OR IGNORE not just IGNORE
 623                 foreach ( $options as $k => $v ) {
 624                         if ( $v == 'IGNORE' ) {
 625                                 $options[$k] = 'OR IGNORE';
 626                         }
 627                 }
 628
 629                 return $options;
 630         }
 631
 632         /**
 633          * @param array $options
 634          * @return string
 635          */
 636         function makeInsertOptions( $options ) {
 637                 $options = self::fixIgnore( $options );
 638
 639                 return parent::makeInsertOptions( $options );
 640         }
 641
 642         /**
 643          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 644          * @param string $table
 645          * @param array $a
 646          * @param string $fname
 647          * @param array $options
 648          * @return bool
 649          */
 650         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 651                 if ( !count( $a ) ) {
 652                         return true;
 653                 }
 654
 655                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 656                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 657                         $affectedRowCount = 0;
 658                         try {
 659                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 660                                 foreach ( $a as $v ) {
 661                                         parent::insert( $table, $v, "$fname/multi-row", $options );
 662                                         $affectedRowCount += $this->affectedRows();
 663                                 }
 664                                 $this->endAtomic( $fname );
 665                         } catch ( Exception $e ) {
 666                                 $this->cancelAtomic( $fname );
 667                                 throw $e;
 668                         }
 669                         $this->affectedRowCount = $affectedRowCount;
 670                 } else {
 671                         parent::insert( $table, $a, "$fname/single-row", $options );
 672                 }
 673
 674                 return true;
 675         }
 676
 677         /**
 678          * @param string $table
 679          * @param array $uniqueIndexes Unused
 680          * @param string|array $rows
 681          * @param string $fname
 682          */
 683         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 684                 if ( !count( $rows ) ) {
 685                         return;
 686                 }
 687
 688                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 689                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 690                         $affectedRowCount = 0;
 691                         try {
 692                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 693                                 foreach ( $rows as $v ) {
 694                                         $this->nativeReplace( $table, $v, "$fname/multi-row" );
 695                                         $affectedRowCount += $this->affectedRows();
 696                                 }
 697                                 $this->endAtomic( $fname );
 698                         } catch ( Exception $e ) {
 699                                 $this->cancelAtomic( $fname );
 700                                 throw $e;
 701                         }
 702                         $this->affectedRowCount = $affectedRowCount;
 703                 } else {
 704                         $this->nativeReplace( $table, $rows, "$fname/single-row" );
 705                 }
 706         }
 707
 708         /**
 709          * Returns the size of a text field, or -1 for "unlimited"
 710          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 711          *
 712          * @param string $table
 713          * @param string $field
 714          * @return int
 715          */
 716         function textFieldSize( $table, $field ) {
 717                 return -1;
 718         }
 719
 720         /**
 721          * @return bool
 722          */
 723         function unionSupportsOrderAndLimit() {
 724                 return false;
 725         }
 726
 727         /**
 728          * @param string[] $sqls
 729          * @param bool $all Whether to "UNION ALL" or not
 730          * @return string
 731          */
 732         function unionQueries( $sqls, $all ) {
 733                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 734
 735                 return implode( $glue, $sqls );
 736         }
 737
 738         /**
 739          * @return bool
 740          */
 741         function wasDeadlock() {
 742                 return $this->lastErrno() == 5; // SQLITE_BUSY
 743         }
 744
 745         /**
 746          * @return bool
 747          */
 748         function wasReadOnlyError() {
 749                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 750         }
 751
 752         public function wasConnectionError( $errno ) {
 753                 return $errno == 17; // SQLITE_SCHEMA;
 754         }
 755
 756         protected function wasKnownStatementRollbackError() {
 757                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 758                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 759                 // https://sqlite.org/lang_createtable.html#uniqueconst
 760                 // https://sqlite.org/lang_conflict.html
 761                 return false;
 762         }
 763
 764         /**
 765          * @return string Wikitext of a link to the server software's web site
 766          */
 767         public function getSoftwareLink() {
 768                 return "[{{int:version-db-sqlite-url}} SQLite]";
 769         }
 770
 771         /**
 772          * @return string Version information from the database
 773          */
 774         function getServerVersion() {
 775                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 776
 777                 return $ver;
 778         }
 779
 780         /**
 781          * Get information about a given field
 782          * Returns false if the field does not exist.
 783          *
 784          * @param string $table
 785          * @param string $field
 786          * @return SQLiteField|bool False on failure
 787          */
 788         function fieldInfo( $table, $field ) {
 789                 $tableName = $this->tableName( $table );
 790                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 791                 $res = $this->query( $sql, __METHOD__ );
 792                 foreach ( $res as $row ) {
 793                         if ( $row->name == $field ) {
 794                                 return new SQLiteField( $row, $tableName );
 795                         }
 796                 }
 797
 798                 return false;
 799         }
 800
 801         protected function doBegin( $fname = '' ) {
 802                 if ( $this->trxMode ) {
 803                         $this->query( "BEGIN {$this->trxMode}", $fname );
 804                 } else {
 805                         $this->query( 'BEGIN', $fname );
 806                 }
 807                 $this->trxLevel = 1;
 808         }
 809
 810         /**
 811          * @param string $s
 812          * @return string
 813          */
 814         function strencode( $s ) {
 815                 return substr( $this->addQuotes( $s ), 1, -1 );
 816         }
 817
 818         /**
 819          * @param string $b
 820          * @return Blob
 821          */
 822         function encodeBlob( $b ) {
 823                 return new Blob( $b );
 824         }
 825
 826         /**
 827          * @param Blob|string $b
 828          * @return string
 829          */
 830         function decodeBlob( $b ) {
 831                 if ( $b instanceof Blob ) {
 832                         $b = $b->fetch();
 833                 }
 834
 835                 return $b;
 836         }
 837
 838         /**
 839          * @param string|int|null|bool|Blob $s
 840          * @return string|int
 841          */
 842         function addQuotes( $s ) {
 843                 if ( $s instanceof Blob ) {
 844                         return "x'" . bin2hex( $s->fetch() ) . "'";
 845                 } elseif ( is_bool( $s ) ) {
 846                         return (int)$s;
 847                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 848                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 849                         // This is a known limitation of SQLite's mprintf function which PDO
 850                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 851                         // https://bugs.php.net/bug.php?id=63419
 852                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 853                         // https://bugs.php.net/bug.php?id=62361
 854                         // There is an additional bug regarding sorting this data after insert
 855                         // on older versions of sqlite shipped with ubuntu 12.04
 856                         // https://phabricator.wikimedia.org/T74367
 857                         $this->queryLogger->debug(
 858                                 __FUNCTION__ .
 859                                 ': Quoting value containing null byte. ' .
 860                                 'For consistency all binary data should have been ' .
 861                                 'first processed with self::encodeBlob()'
 862                         );
 863                         return "x'" . bin2hex( (string)$s ) . "'";
 864                 } else {
 865                         return $this->getBindingHandle()->quote( (string)$s );
 866                 }
 867         }
 868
 869         public function buildSubstring( $input, $startPosition, $length = null ) {
 870                 $this->assertBuildSubstringParams( $startPosition, $length );
 871                 $params = [ $input, $startPosition ];
 872                 if ( $length !== null ) {
 873                         $params[] = $length;
 874                 }
 875                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 876         }
 877
 878         /**
 879          * @param string $field Field or column to cast
 880          * @return string
 881          * @since 1.28
 882          */
 883         public function buildStringCast( $field ) {
 884                 return 'CAST ( ' . $field . ' AS TEXT )';
 885         }
 886
 887         /**
 888          * No-op version of deadlockLoop
 889          *
 890          * @return mixed
 891          */
 892         public function deadlockLoop( /*...*/ ) {
 893                 $args = func_get_args();
 894                 $function = array_shift( $args );
 895
 896                 return $function( ...$args );
 897         }
 898
 899         /**
 900          * @param string $s
 901          * @return string
 902          */
 903         protected function replaceVars( $s ) {
 904                 $s = parent::replaceVars( $s );
 905                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 906                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 907
 908                         // binary/varbinary column type -> blob
 909                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 910                         // no such thing as unsigned
 911                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 912                         // INT -> INTEGER
 913                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 914                         // floating point types -> REAL
 915                         $s = preg_replace(
 916                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 917                                 'REAL',
 918                                 $s
 919                         );
 920                         // varchar -> TEXT
 921                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 922                         // TEXT normalization
 923                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 924                         // BLOB normalization
 925                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 926                         // BOOL -> INTEGER
 927                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 928                         // DATETIME -> TEXT
 929                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 930                         // No ENUM type
 931                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 932                         // binary collation type -> nothing
 933                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 934                         // auto_increment -> autoincrement
 935                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 936                         // No explicit options
 937                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 938                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 939                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 940                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 941                         // No truncated indexes
 942                         $s = preg_replace( '/\(\d+\)/', '', $s );
 943                         // No FULLTEXT
 944                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 945                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 946                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 947                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 948                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 949                         // INSERT IGNORE --> INSERT OR IGNORE
 950                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 951                 }
 952
 953                 return $s;
 954         }
 955
 956         public function lock( $lockName, $method, $timeout = 5 ) {
 957                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 958                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 959                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 960                         }
 961                 }
 962
 963                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 964         }
 965
 966         public function unlock( $lockName, $method ) {
 967                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 968         }
 969
 970         /**
 971          * Build a concatenation list to feed into a SQL query
 972          *
 973          * @param string[] $stringList
 974          * @return string
 975          */
 976         function buildConcat( $stringList ) {
 977                 return '(' . implode( ') || (', $stringList ) . ')';
 978         }
 979
 980         public function buildGroupConcatField(
 981                 $delim, $table, $field, $conds = '', $join_conds = []
 982         ) {
 983                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 984
 985                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 986         }
 987
 988         /**
 989          * @param string $oldName
 990          * @param string $newName
 991          * @param bool $temporary
 992          * @param string $fname
 993          * @return bool|ResultWrapper
 994          * @throws RuntimeException
 995          */
 996         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 997                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 998                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 999                 $obj = $this->fetchObject( $res );
1000                 if ( !$obj ) {
1001                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
1002                 }
1003                 $sql = $obj->sql;
1004                 $sql = preg_replace(
1005                         '/(?<=\W)"?' .
1006                                 preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
1007                                 '"?(?=\W)/',
1008                         $this->addIdentifierQuotes( $newName ),
1009                         $sql,
1010                         1
1011                 );
1012                 if ( $temporary ) {
1013                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
1014                                 $this->queryLogger->debug(
1015                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
1016                         } else {
1017                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
1018                         }
1019                 }
1020
1021                 $res = $this->query( $sql, $fname, self::QUERY_PSEUDO_PERMANENT );
1022
1023                 // Take over indexes
1024                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
1025                 foreach ( $indexList as $index ) {
1026                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
1027                                 continue;
1028                         }
1029
1030                         if ( $index->unique ) {
1031                                 $sql = 'CREATE UNIQUE INDEX';
1032                         } else {
1033                                 $sql = 'CREATE INDEX';
1034                         }
1035                         // Try to come up with a new index name, given indexes have database scope in SQLite
1036                         $indexName = $newName . '_' . $index->name;
1037                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1038
1039                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1040                         $fields = [];
1041                         foreach ( $indexInfo as $indexInfoRow ) {
1042                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1043                         }
1044
1045                         $sql .= '(' . implode( ',', $fields ) . ')';
1046
1047                         $this->query( $sql );
1048                 }
1049
1050                 return $res;
1051         }
1052
1053         /**
1054          * List all tables on the database
1055          *
1056          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1057          * @param string $fname Calling function name
1058          *
1059          * @return array
1060          */
1061         function listTables( $prefix = null, $fname = __METHOD__ ) {
1062                 $result = $this->select(
1063                         'sqlite_master',
1064                         'name',
1065                         "type='table'"
1066                 );
1067
1068                 $endArray = [];
1069
1070                 foreach ( $result as $table ) {
1071                         $vars = get_object_vars( $table );
1072                         $table = array_pop( $vars );
1073
1074                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1075                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1076                                         $endArray[] = $table;
1077                                 }
1078                         }
1079                 }
1080
1081                 return $endArray;
1082         }
1083
1084         /**
1085          * Override due to no CASCADE support
1086          *
1087          * @param string $tableName
1088          * @param string $fName
1089          * @return bool|ResultWrapper
1090          * @throws DBReadOnlyError
1091          */
1092         public function dropTable( $tableName, $fName = __METHOD__ ) {
1093                 if ( !$this->tableExists( $tableName, $fName ) ) {
1094                         return false;
1095                 }
1096                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1097
1098                 return $this->query( $sql, $fName );
1099         }
1100
1101         public function setTableAliases( array $aliases ) {
1102                 parent::setTableAliases( $aliases );
1103                 foreach ( $this->tableAliases as $params ) {
1104                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1105                                 continue;
1106                         }
1107                         $this->attachDatabase( $params['dbname'] );
1108                         $this->alreadyAttached[$params['dbname']] = true;
1109                 }
1110         }
1111
1112         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1113                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1114                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1115                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1116         }
1117
1118         public function databasesAreIndependent() {
1119                 return true;
1120         }
1121
1122         /**
1123          * @return string
1124          */
1125         public function __toString() {
1126                 return is_object( $this->conn )
1127                         ? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
1128                         : '(not connected)';
1129         }
1130
1131         /**
1132          * @return PDO
1133          */
1134         protected function getBindingHandle() {
1135                 return parent::getBindingHandle();
1136         }
1137 }
1138
1139 /**
1140  * @deprecated since 1.29
1141  */
1142 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );