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 NullLockManager;
  27 use PDO;
  28 use PDOException;
  29 use Exception;
  30 use LockManager;
  31 use FSLockManager;
  32 use RuntimeException;
  33 use stdClass;
  34
  35 /**
  36  * @ingroup Database
  37  */
  38 class DatabaseSqlite extends Database {
  39         /** @var string|null Directory for SQLite database files listed under their DB name */
  40         protected $dbDir;
  41         /** @var string|null Explicit path for the SQLite database file */
  42         protected $dbPath;
  43         /** @var string Transaction mode */
  44         protected $trxMode;
  45
  46         /** @var int The number of rows affected as an integer */
  47         protected $lastAffectedRowCount;
  48         /** @var resource */
  49         protected $lastResultHandle;
  50
  51         /** @var PDO */
  52         protected $conn;
  53
  54         /** @var FSLockManager (hopefully on the same server as the DB) */
  55         protected $lockMgr;
  56
  57         /** @var array List of shared database already attached to this connection */
  58         private $sessionAttachedDbs = [];
  59
  60         /** @var string[] See https://www.sqlite.org/lang_transaction.html */
  61         private static $VALID_TRX_MODES = [ '', 'DEFERRED', 'IMMEDIATE', 'EXCLUSIVE' ];
  62
  63         /**
  64          * Additional params include:
  65          *   - dbDirectory : directory containing the DB and the lock file directory
  66          *   - dbFilePath  : use this to force the path of the DB file
  67          *   - trxMode     : one of (deferred, immediate, exclusive)
  68          * @param array $p
  69          */
  70         public function __construct( array $p ) {
  71                 if ( isset( $p['dbFilePath'] ) ) {
  72                         $this->dbPath = $p['dbFilePath'];
  73                         if ( !strlen( $p['dbname'] ) ) {
  74                                 $p['dbname'] = self::generateDatabaseName( $this->dbPath );
  75                         }
  76                 } elseif ( isset( $p['dbDirectory'] ) ) {
  77                         $this->dbDir = $p['dbDirectory'];
  78                 }
  79
  80                 parent::__construct( $p );
  81
  82                 $this->trxMode = strtoupper( $p['trxMode'] ?? '' );
  83
  84                 $lockDirectory = $this->getLockFileDirectory();
  85                 if ( $lockDirectory !== null ) {
  86                         $this->lockMgr = new FSLockManager( [
  87                                 'domain' => $this->getDomainID(),
  88                                 'lockDirectory' => $lockDirectory
  89                         ] );
  90                 } else {
  91                         $this->lockMgr = new NullLockManager( [ 'domain' => $this->getDomainID() ] );
  92                 }
  93         }
  94
  95         protected static function getAttributes() {
  96                 return [ self::ATTR_DB_LEVEL_LOCKING => true ];
  97         }
  98
  99         /**
 100          * @param string $filename
 101          * @param array $p Options map; supports:
 102          *   - flags       : (same as __construct counterpart)
 103          *   - trxMode     : (same as __construct counterpart)
 104          *   - dbDirectory : (same as __construct counterpart)
 105          * @return DatabaseSqlite
 106          * @since 1.25
 107          */
 108         public static function newStandaloneInstance( $filename, array $p = [] ) {
 109                 $p['dbFilePath'] = $filename;
 110                 $p['schema'] = null;
 111                 $p['tablePrefix'] = '';
 112                 /** @var DatabaseSqlite $db */
 113                 $db = Database::factory( 'sqlite', $p );
 114
 115                 return $db;
 116         }
 117
 118         /**
 119          * @return string
 120          */
 121         public function getType() {
 122                 return 'sqlite';
 123         }
 124
 125         protected function open( $server, $user, $pass, $dbName, $schema, $tablePrefix ) {
 126                 $this->close();
 127
 128                 // Note that for SQLite, $server, $user, and $pass are ignored
 129
 130                 if ( $schema !== null ) {
 131                         throw $this->newExceptionAfterConnectError( "Got schema '$schema'; not supported." );
 132                 }
 133
 134                 if ( $this->dbPath !== null ) {
 135                         $path = $this->dbPath;
 136                 } elseif ( $this->dbDir !== null ) {
 137                         $path = self::generateFileName( $this->dbDir, $dbName );
 138                 } else {
 139                         throw $this->newExceptionAfterConnectError( "DB path or directory required" );
 140                 }
 141
 142                 // Check if the database file already exists but is non-readable
 143                 if (
 144                         !self::isProcessMemoryPath( $path ) &&
 145                         file_exists( $path ) &&
 146                         !is_readable( $path )
 147                 ) {
 148                         throw $this->newExceptionAfterConnectError( 'SQLite database file is not readable' );
 149                 } elseif ( !in_array( $this->trxMode, self::$VALID_TRX_MODES, true ) ) {
 150                         throw $this->newExceptionAfterConnectError( "Got mode '{$this->trxMode}' for BEGIN" );
 151                 }
 152
 153                 $attributes = [];
 154                 if ( $this->getFlag( self::DBO_PERSISTENT ) ) {
 155                         // Persistent connections can avoid some schema index reading overhead.
 156                         // On the other hand, they can cause horrible contention with DBO_TRX.
 157                         if ( $this->getFlag( self::DBO_TRX ) || $this->getFlag( self::DBO_DEFAULT ) ) {
 158                                 $this->connLogger->warning(
 159                                         __METHOD__ . ": ignoring DBO_PERSISTENT due to DBO_TRX or DBO_DEFAULT",
 160                                         $this->getLogContext()
 161                                 );
 162                         } else {
 163                                 $attributes[PDO::ATTR_PERSISTENT] = true;
 164                         }
 165                 }
 166
 167                 try {
 168                         // Open the database file, creating it if it does not yet exist
 169                         $this->conn = new PDO( "sqlite:$path", null, null, $attributes );
 170                 } catch ( PDOException $e ) {
 171                         throw $this->newExceptionAfterConnectError( $e->getMessage() );
 172                 }
 173
 174                 $this->currentDomain = new DatabaseDomain( $dbName, null, $tablePrefix );
 175
 176                 try {
 177                         $flags = self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY;
 178                         // Enforce LIKE to be case sensitive, just like MySQL
 179                         $this->query( 'PRAGMA case_sensitive_like = 1', __METHOD__, $flags );
 180                         // Apply optimizations or requirements regarding fsync() usage
 181                         $sync = $this->connectionVariables['synchronous'] ?? null;
 182                         if ( in_array( $sync, [ 'EXTRA', 'FULL', 'NORMAL', 'OFF' ], true ) ) {
 183                                 $this->query( "PRAGMA synchronous = $sync", __METHOD__, $flags );
 184                         }
 185                         $this->attachDatabasesFromTableAliases();
 186                 } catch ( Exception $e ) {
 187                         throw $this->newExceptionAfterConnectError( $e->getMessage() );
 188                 }
 189         }
 190
 191         /**
 192          * @return string|null SQLite DB file path
 193          * @throws DBUnexpectedError
 194          * @since 1.25
 195          */
 196         public function getDbFilePath() {
 197                 return $this->dbPath ?? self::generateFileName( $this->dbDir, $this->getDBname() );
 198         }
 199
 200         /**
 201          * @return string|null Lock file directory
 202          */
 203         public function getLockFileDirectory() {
 204                 if ( $this->dbPath !== null && !self::isProcessMemoryPath( $this->dbPath ) ) {
 205                         return dirname( $this->dbPath ) . '/locks';
 206                 } elseif ( $this->dbDir !== null && !self::isProcessMemoryPath( $this->dbDir ) ) {
 207                         return $this->dbDir . '/locks';
 208                 }
 209
 210                 return null;
 211         }
 212
 213         /**
 214          * Does not actually close the connection, just destroys the reference for GC to do its work
 215          * @return bool
 216          */
 217         protected function closeConnection() {
 218                 $this->conn = null;
 219
 220                 return true;
 221         }
 222
 223         /**
 224          * Generates a database file name. Explicitly public for installer.
 225          * @param string $dir Directory where database resides
 226          * @param string|bool $dbName Database name (or false from Database::factory, validated here)
 227          * @return string
 228          * @throws DBUnexpectedError
 229          */
 230         public static function generateFileName( $dir, $dbName ) {
 231                 if ( $dir == '' ) {
 232                         throw new DBUnexpectedError( null, __CLASS__ . ": no DB directory specified" );
 233                 } elseif ( self::isProcessMemoryPath( $dir ) ) {
 234                         throw new DBUnexpectedError(
 235                                 null,
 236                                 __CLASS__ . ": cannot use process memory directory '$dir'"
 237                         );
 238                 } elseif ( !strlen( $dbName ) ) {
 239                         throw new DBUnexpectedError( null, __CLASS__ . ": no DB name specified" );
 240                 }
 241
 242                 return "$dir/$dbName.sqlite";
 243         }
 244
 245         /**
 246          * @param string $path
 247          * @return string
 248          */
 249         private static function generateDatabaseName( $path ) {
 250                 if ( preg_match( '/^(:memory:$|file::memory:)/', $path ) ) {
 251                         // E.g. "file::memory:?cache=shared" => ":memory":
 252                         return ':memory:';
 253                 } elseif ( preg_match( '/^file::([^?]+)\?mode=memory(&|$)/', $path, $m ) ) {
 254                         // E.g. "file:memdb1?mode=memory" => ":memdb1:"
 255                         return ":{$m[1]}:";
 256                 } else {
 257                         // E.g. "/home/.../some_db.sqlite3" => "some_db"
 258                         return preg_replace( '/\.sqlite\d?$/', '', basename( $path ) );
 259                 }
 260         }
 261
 262         /**
 263          * @param string $path
 264          * @return bool
 265          */
 266         private static function isProcessMemoryPath( $path ) {
 267                 return preg_match( '/^(:memory:$|file:(:memory:|[^?]+\?mode=memory(&|$)))/', $path );
 268         }
 269
 270         /**
 271          * Returns version of currently supported SQLite fulltext search module or false if none present.
 272          * @return string
 273          */
 274         static function getFulltextSearchModule() {
 275                 static $cachedResult = null;
 276                 if ( $cachedResult !== null ) {
 277                         return $cachedResult;
 278                 }
 279                 $cachedResult = false;
 280                 $table = 'dummy_search_test';
 281
 282                 $db = self::newStandaloneInstance( ':memory:' );
 283                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 284                         $cachedResult = 'FTS3';
 285                 }
 286                 $db->close();
 287
 288                 return $cachedResult;
 289         }
 290
 291         /**
 292          * Attaches external database to the connection handle
 293          *
 294          * @see https://sqlite.org/lang_attach.html
 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 IResultWrapper
 302          */
 303         public function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 304                 $file = is_string( $file ) ? $file : self::generateFileName( $this->dbDir, $name );
 305                 $encFile = $this->addQuotes( $file );
 306
 307                 return $this->query(
 308                         "ATTACH DATABASE $encFile AS $name",
 309                         $fname,
 310                         self::QUERY_IGNORE_DBO_TRX
 311                 );
 312         }
 313
 314         protected function isWriteQuery( $sql ) {
 315                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 316         }
 317
 318         protected function isTransactableQuery( $sql ) {
 319                 return parent::isTransactableQuery( $sql ) && !in_array(
 320                         $this->getQueryVerb( $sql ),
 321                         [ 'ATTACH', 'PRAGMA' ],
 322                         true
 323                 );
 324         }
 325
 326         /**
 327          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 328          *
 329          * @param string $sql
 330          * @return bool|IResultWrapper
 331          */
 332         protected function doQuery( $sql ) {
 333                 $res = $this->getBindingHandle()->query( $sql );
 334                 if ( $res === false ) {
 335                         return false;
 336                 }
 337
 338                 $resource = ResultWrapper::unwrap( $res );
 339                 $this->lastAffectedRowCount = $resource->rowCount();
 340                 $res = new ResultWrapper( $this, $resource->fetchAll() );
 341
 342                 return $res;
 343         }
 344
 345         /**
 346          * @param IResultWrapper|mixed $res
 347          */
 348         function freeResult( $res ) {
 349                 if ( $res instanceof ResultWrapper ) {
 350                         $res->free();
 351                 }
 352         }
 353
 354         /**
 355          * @param IResultWrapper|array $res
 356          * @return stdClass|bool
 357          */
 358         function fetchObject( $res ) {
 359                 $resource =& ResultWrapper::unwrap( $res );
 360
 361                 $cur = current( $resource );
 362                 if ( is_array( $cur ) ) {
 363                         next( $resource );
 364                         $obj = new stdClass;
 365                         foreach ( $cur as $k => $v ) {
 366                                 if ( !is_numeric( $k ) ) {
 367                                         $obj->$k = $v;
 368                                 }
 369                         }
 370
 371                         return $obj;
 372                 }
 373
 374                 return false;
 375         }
 376
 377         /**
 378          * @param IResultWrapper|mixed $res
 379          * @return array|bool
 380          */
 381         function fetchRow( $res ) {
 382                 $resource =& ResultWrapper::unwrap( $res );
 383                 $cur = current( $resource );
 384                 if ( is_array( $cur ) ) {
 385                         next( $resource );
 386
 387                         return $cur;
 388                 }
 389
 390                 return false;
 391         }
 392
 393         /**
 394          * The PDO::Statement class implements the array interface so count() will work
 395          *
 396          * @param IResultWrapper|array|false $res
 397          * @return int
 398          */
 399         function numRows( $res ) {
 400                 // false does not implement Countable
 401                 $resource = ResultWrapper::unwrap( $res );
 402
 403                 return is_array( $resource ) ? count( $resource ) : 0;
 404         }
 405
 406         /**
 407          * @param IResultWrapper $res
 408          * @return int
 409          */
 410         function numFields( $res ) {
 411                 $resource = ResultWrapper::unwrap( $res );
 412                 if ( is_array( $resource ) && count( $resource ) > 0 ) {
 413                         // The size of the result array is twice the number of fields. (T67578)
 414                         return count( $resource[0] ) / 2;
 415                 } else {
 416                         // If the result is empty return 0
 417                         return 0;
 418                 }
 419         }
 420
 421         /**
 422          * @param IResultWrapper $res
 423          * @param int $n
 424          * @return bool
 425          */
 426         function fieldName( $res, $n ) {
 427                 $resource = ResultWrapper::unwrap( $res );
 428                 if ( is_array( $resource ) ) {
 429                         $keys = array_keys( $resource[0] );
 430
 431                         return $keys[$n];
 432                 }
 433
 434                 return false;
 435         }
 436
 437         protected function doSelectDomain( DatabaseDomain $domain ) {
 438                 if ( $domain->getSchema() !== null ) {
 439                         throw new DBExpectedError(
 440                                 $this,
 441                                 __CLASS__ . ": domain '{$domain->getId()}' has a schema component"
 442                         );
 443                 }
 444
 445                 $database = $domain->getDatabase();
 446                 // A null database means "don't care" so leave it as is and update the table prefix
 447                 if ( $database === null ) {
 448                         $this->currentDomain = new DatabaseDomain(
 449                                 $this->currentDomain->getDatabase(),
 450                                 null,
 451                                 $domain->getTablePrefix()
 452                         );
 453
 454                         return true;
 455                 }
 456
 457                 if ( $database !== $this->getDBname() ) {
 458                         throw new DBExpectedError(
 459                                 $this,
 460                                 __CLASS__ . ": cannot change database (got '$database')"
 461                         );
 462                 }
 463
 464                 return true;
 465         }
 466
 467         /**
 468          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 469          *
 470          * @param string $name
 471          * @param string $format
 472          * @return string
 473          */
 474         function tableName( $name, $format = 'quoted' ) {
 475                 // table names starting with sqlite_ are reserved
 476                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 477                         return $name;
 478                 }
 479
 480                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 481         }
 482
 483         /**
 484          * This must be called after nextSequenceVal
 485          *
 486          * @return int
 487          */
 488         function insertId() {
 489                 // PDO::lastInsertId yields a string :(
 490                 return intval( $this->getBindingHandle()->lastInsertId() );
 491         }
 492
 493         /**
 494          * @param IResultWrapper|array $res
 495          * @param int $row
 496          */
 497         function dataSeek( $res, $row ) {
 498                 $resource =& ResultWrapper::unwrap( $res );
 499                 reset( $resource );
 500                 if ( $row > 0 ) {
 501                         for ( $i = 0; $i < $row; $i++ ) {
 502                                 next( $resource );
 503                         }
 504                 }
 505         }
 506
 507         /**
 508          * @return string
 509          */
 510         function lastError() {
 511                 if ( !is_object( $this->conn ) ) {
 512                         return "Cannot return last error, no db connection";
 513                 }
 514                 $e = $this->conn->errorInfo();
 515
 516                 return $e[2] ?? '';
 517         }
 518
 519         /**
 520          * @return string
 521          */
 522         function lastErrno() {
 523                 if ( !is_object( $this->conn ) ) {
 524                         return "Cannot return last error, no db connection";
 525                 } else {
 526                         $info = $this->conn->errorInfo();
 527
 528                         return $info[1];
 529                 }
 530         }
 531
 532         /**
 533          * @return int
 534          */
 535         protected function fetchAffectedRowCount() {
 536                 return $this->lastAffectedRowCount;
 537         }
 538
 539         function tableExists( $table, $fname = __METHOD__ ) {
 540                 $tableRaw = $this->tableName( $table, 'raw' );
 541                 if ( isset( $this->sessionTempTables[$tableRaw] ) ) {
 542                         return true; // already known to exist
 543                 }
 544
 545                 $encTable = $this->addQuotes( $tableRaw );
 546                 $res = $this->query(
 547                         "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable",
 548                         __METHOD__,
 549                         self::QUERY_IGNORE_DBO_TRX
 550                 );
 551
 552                 return $res->numRows() ? true : false;
 553         }
 554
 555         /**
 556          * Returns information about an index
 557          * Returns false if the index does not exist
 558          * - if errors are explicitly ignored, returns NULL on failure
 559          *
 560          * @param string $table
 561          * @param string $index
 562          * @param string $fname
 563          * @return array|false
 564          */
 565         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 566                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 567                 $res = $this->query( $sql, $fname, self::QUERY_IGNORE_DBO_TRX );
 568                 if ( !$res || $res->numRows() == 0 ) {
 569                         return false;
 570                 }
 571                 $info = [];
 572                 foreach ( $res as $row ) {
 573                         $info[] = $row->name;
 574                 }
 575
 576                 return $info;
 577         }
 578
 579         /**
 580          * @param string $table
 581          * @param string $index
 582          * @param string $fname
 583          * @return bool|null
 584          */
 585         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 586                 $row = $this->selectRow( 'sqlite_master', '*',
 587                         [
 588                                 'type' => 'index',
 589                                 'name' => $this->indexName( $index ),
 590                         ], $fname );
 591                 if ( !$row || !isset( $row->sql ) ) {
 592                         return null;
 593                 }
 594
 595                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 596                 $indexPos = strpos( $row->sql, 'INDEX' );
 597                 if ( $indexPos === false ) {
 598                         return null;
 599                 }
 600                 $firstPart = substr( $row->sql, 0, $indexPos );
 601                 $options = explode( ' ', $firstPart );
 602
 603                 return in_array( 'UNIQUE', $options );
 604         }
 605
 606         protected function makeSelectOptions( array $options ) {
 607                 // Remove problematic options that the base implementation converts to SQL
 608                 foreach ( $options as $k => $v ) {
 609                         if ( is_numeric( $k ) && ( $v === 'FOR UPDATE' || $v === 'LOCK IN SHARE MODE' ) ) {
 610                                 $options[$k] = '';
 611                         }
 612                 }
 613
 614                 return parent::makeSelectOptions( $options );
 615         }
 616
 617         /**
 618          * @param array $options
 619          * @return array
 620          */
 621         protected function makeUpdateOptionsArray( $options ) {
 622                 $options = parent::makeUpdateOptionsArray( $options );
 623                 $options = self::fixIgnore( $options );
 624
 625                 return $options;
 626         }
 627
 628         /**
 629          * @param array $options
 630          * @return array
 631          */
 632         static function fixIgnore( $options ) {
 633                 # SQLite uses OR IGNORE not just IGNORE
 634                 foreach ( $options as $k => $v ) {
 635                         if ( $v == 'IGNORE' ) {
 636                                 $options[$k] = 'OR IGNORE';
 637                         }
 638                 }
 639
 640                 return $options;
 641         }
 642
 643         /**
 644          * @param array $options
 645          * @return string
 646          */
 647         function makeInsertOptions( $options ) {
 648                 $options = self::fixIgnore( $options );
 649
 650                 return parent::makeInsertOptions( $options );
 651         }
 652
 653         /**
 654          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 655          * @param string $table
 656          * @param array $a
 657          * @param string $fname
 658          * @param array $options
 659          * @return bool
 660          */
 661         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 662                 if ( !count( $a ) ) {
 663                         return true;
 664                 }
 665
 666                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 667                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 668                         $affectedRowCount = 0;
 669                         try {
 670                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 671                                 foreach ( $a as $v ) {
 672                                         parent::insert( $table, $v, "$fname/multi-row", $options );
 673                                         $affectedRowCount += $this->affectedRows();
 674                                 }
 675                                 $this->endAtomic( $fname );
 676                         } catch ( Exception $e ) {
 677                                 $this->cancelAtomic( $fname );
 678                                 throw $e;
 679                         }
 680                         $this->affectedRowCount = $affectedRowCount;
 681                 } else {
 682                         parent::insert( $table, $a, "$fname/single-row", $options );
 683                 }
 684
 685                 return true;
 686         }
 687
 688         /**
 689          * @param string $table
 690          * @param array $uniqueIndexes Unused
 691          * @param string|array $rows
 692          * @param string $fname
 693          */
 694         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 695                 if ( !count( $rows ) ) {
 696                         return;
 697                 }
 698
 699                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 700                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 701                         $affectedRowCount = 0;
 702                         try {
 703                                 $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
 704                                 foreach ( $rows as $v ) {
 705                                         $this->nativeReplace( $table, $v, "$fname/multi-row" );
 706                                         $affectedRowCount += $this->affectedRows();
 707                                 }
 708                                 $this->endAtomic( $fname );
 709                         } catch ( Exception $e ) {
 710                                 $this->cancelAtomic( $fname );
 711                                 throw $e;
 712                         }
 713                         $this->affectedRowCount = $affectedRowCount;
 714                 } else {
 715                         $this->nativeReplace( $table, $rows, "$fname/single-row" );
 716                 }
 717         }
 718
 719         /**
 720          * Returns the size of a text field, or -1 for "unlimited"
 721          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 722          *
 723          * @param string $table
 724          * @param string $field
 725          * @return int
 726          */
 727         function textFieldSize( $table, $field ) {
 728                 return -1;
 729         }
 730
 731         /**
 732          * @return bool
 733          */
 734         function unionSupportsOrderAndLimit() {
 735                 return false;
 736         }
 737
 738         /**
 739          * @param string[] $sqls
 740          * @param bool $all Whether to "UNION ALL" or not
 741          * @return string
 742          */
 743         function unionQueries( $sqls, $all ) {
 744                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 745
 746                 return implode( $glue, $sqls );
 747         }
 748
 749         /**
 750          * @return bool
 751          */
 752         function wasDeadlock() {
 753                 return $this->lastErrno() == 5; // SQLITE_BUSY
 754         }
 755
 756         /**
 757          * @return bool
 758          */
 759         function wasReadOnlyError() {
 760                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 761         }
 762
 763         public function wasConnectionError( $errno ) {
 764                 return $errno == 17; // SQLITE_SCHEMA;
 765         }
 766
 767         protected function wasKnownStatementRollbackError() {
 768                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 769                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 770                 // https://sqlite.org/lang_createtable.html#uniqueconst
 771                 // https://sqlite.org/lang_conflict.html
 772                 return false;
 773         }
 774
 775         public function serverIsReadOnly() {
 776                 $this->assertHasConnectionHandle();
 777
 778                 $path = $this->getDbFilePath();
 779
 780                 return ( !self::isProcessMemoryPath( $path ) && !is_writable( $path ) );
 781         }
 782
 783         /**
 784          * @return string Wikitext of a link to the server software's web site
 785          */
 786         public function getSoftwareLink() {
 787                 return "[{{int:version-db-sqlite-url}} SQLite]";
 788         }
 789
 790         /**
 791          * @return string Version information from the database
 792          */
 793         function getServerVersion() {
 794                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 795
 796                 return $ver;
 797         }
 798
 799         /**
 800          * Get information about a given field
 801          * Returns false if the field does not exist.
 802          *
 803          * @param string $table
 804          * @param string $field
 805          * @return SQLiteField|bool False on failure
 806          */
 807         function fieldInfo( $table, $field ) {
 808                 $tableName = $this->tableName( $table );
 809                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 810                 $res = $this->query( $sql, __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 811                 foreach ( $res as $row ) {
 812                         if ( $row->name == $field ) {
 813                                 return new SQLiteField( $row, $tableName );
 814                         }
 815                 }
 816
 817                 return false;
 818         }
 819
 820         protected function doBegin( $fname = '' ) {
 821                 if ( $this->trxMode != '' ) {
 822                         $this->query( "BEGIN {$this->trxMode}", $fname );
 823                 } else {
 824                         $this->query( 'BEGIN', $fname );
 825                 }
 826         }
 827
 828         /**
 829          * @param string $s
 830          * @return string
 831          */
 832         function strencode( $s ) {
 833                 return substr( $this->addQuotes( $s ), 1, -1 );
 834         }
 835
 836         /**
 837          * @param string $b
 838          * @return Blob
 839          */
 840         function encodeBlob( $b ) {
 841                 return new Blob( $b );
 842         }
 843
 844         /**
 845          * @param Blob|string $b
 846          * @return string
 847          */
 848         function decodeBlob( $b ) {
 849                 if ( $b instanceof Blob ) {
 850                         $b = $b->fetch();
 851                 }
 852
 853                 return $b;
 854         }
 855
 856         /**
 857          * @param string|int|null|bool|Blob $s
 858          * @return string|int
 859          */
 860         function addQuotes( $s ) {
 861                 if ( $s instanceof Blob ) {
 862                         return "x'" . bin2hex( $s->fetch() ) . "'";
 863                 } elseif ( is_bool( $s ) ) {
 864                         return (int)$s;
 865                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 866                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 867                         // This is a known limitation of SQLite's mprintf function which PDO
 868                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 869                         // https://bugs.php.net/bug.php?id=63419
 870                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 871                         // https://bugs.php.net/bug.php?id=62361
 872                         // There is an additional bug regarding sorting this data after insert
 873                         // on older versions of sqlite shipped with ubuntu 12.04
 874                         // https://phabricator.wikimedia.org/T74367
 875                         $this->queryLogger->debug(
 876                                 __FUNCTION__ .
 877                                 ': Quoting value containing null byte. ' .
 878                                 'For consistency all binary data should have been ' .
 879                                 'first processed with self::encodeBlob()'
 880                         );
 881                         return "x'" . bin2hex( (string)$s ) . "'";
 882                 } else {
 883                         return $this->getBindingHandle()->quote( (string)$s );
 884                 }
 885         }
 886
 887         public function buildSubstring( $input, $startPosition, $length = null ) {
 888                 $this->assertBuildSubstringParams( $startPosition, $length );
 889                 $params = [ $input, $startPosition ];
 890                 if ( $length !== null ) {
 891                         $params[] = $length;
 892                 }
 893                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 894         }
 895
 896         /**
 897          * @param string $field Field or column to cast
 898          * @return string
 899          * @since 1.28
 900          */
 901         public function buildStringCast( $field ) {
 902                 return 'CAST ( ' . $field . ' AS TEXT )';
 903         }
 904
 905         /**
 906          * No-op version of deadlockLoop
 907          *
 908          * @return mixed
 909          */
 910         public function deadlockLoop( /*...*/ ) {
 911                 $args = func_get_args();
 912                 $function = array_shift( $args );
 913
 914                 return $function( ...$args );
 915         }
 916
 917         /**
 918          * @param string $s
 919          * @return string
 920          */
 921         protected function replaceVars( $s ) {
 922                 $s = parent::replaceVars( $s );
 923                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 924                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 925
 926                         // binary/varbinary column type -> blob
 927                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 928                         // no such thing as unsigned
 929                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 930                         // INT -> INTEGER
 931                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 932                         // floating point types -> REAL
 933                         $s = preg_replace(
 934                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 935                                 'REAL',
 936                                 $s
 937                         );
 938                         // varchar -> TEXT
 939                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 940                         // TEXT normalization
 941                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 942                         // BLOB normalization
 943                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 944                         // BOOL -> INTEGER
 945                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 946                         // DATETIME -> TEXT
 947                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 948                         // No ENUM type
 949                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 950                         // binary collation type -> nothing
 951                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 952                         // auto_increment -> autoincrement
 953                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 954                         // No explicit options
 955                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 956                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 957                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 958                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 959                         // No truncated indexes
 960                         $s = preg_replace( '/\(\d+\)/', '', $s );
 961                         // No FULLTEXT
 962                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 963                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 964                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 965                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 966                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 967                         // INSERT IGNORE --> INSERT OR IGNORE
 968                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 969                 }
 970
 971                 return $s;
 972         }
 973
 974         public function lock( $lockName, $method, $timeout = 5 ) {
 975                 $status = $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout );
 976                 if (
 977                         $this->lockMgr instanceof FSLockManager &&
 978                         $status->hasMessage( 'lockmanager-fail-openlock' )
 979                 ) {
 980                         throw new DBError( $this, "Cannot create directory \"{$this->getLockFileDirectory()}\"" );
 981                 }
 982
 983                 return $status->isOK();
 984         }
 985
 986         public function unlock( $lockName, $method ) {
 987                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isGood();
 988         }
 989
 990         /**
 991          * Build a concatenation list to feed into a SQL query
 992          *
 993          * @param string[] $stringList
 994          * @return string
 995          */
 996         function buildConcat( $stringList ) {
 997                 return '(' . implode( ') || (', $stringList ) . ')';
 998         }
 999
1000         public function buildGroupConcatField(
1001                 $delim, $table, $field, $conds = '', $join_conds = []
1002         ) {
1003                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
1004
1005                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1006         }
1007
1008         /**
1009          * @param string $oldName
1010          * @param string $newName
1011          * @param bool $temporary
1012          * @param string $fname
1013          * @return bool|IResultWrapper
1014          * @throws RuntimeException
1015          */
1016         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1017                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
1018                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
1019                 $obj = $this->fetchObject( $res );
1020                 if ( !$obj ) {
1021                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
1022                 }
1023                 $sql = $obj->sql;
1024                 $sql = preg_replace(
1025                         '/(?<=\W)"?' .
1026                                 preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
1027                                 '"?(?=\W)/',
1028                         $this->addIdentifierQuotes( $newName ),
1029                         $sql,
1030                         1
1031                 );
1032                 if ( $temporary ) {
1033                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
1034                                 $this->queryLogger->debug(
1035                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
1036                         } else {
1037                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
1038                         }
1039                 }
1040
1041                 $res = $this->query( $sql, $fname, self::QUERY_PSEUDO_PERMANENT );
1042
1043                 // Take over indexes
1044                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
1045                 foreach ( $indexList as $index ) {
1046                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
1047                                 continue;
1048                         }
1049
1050                         if ( $index->unique ) {
1051                                 $sql = 'CREATE UNIQUE INDEX';
1052                         } else {
1053                                 $sql = 'CREATE INDEX';
1054                         }
1055                         // Try to come up with a new index name, given indexes have database scope in SQLite
1056                         $indexName = $newName . '_' . $index->name;
1057                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1058
1059                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1060                         $fields = [];
1061                         foreach ( $indexInfo as $indexInfoRow ) {
1062                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1063                         }
1064
1065                         $sql .= '(' . implode( ',', $fields ) . ')';
1066
1067                         $this->query( $sql );
1068                 }
1069
1070                 return $res;
1071         }
1072
1073         /**
1074          * List all tables on the database
1075          *
1076          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1077          * @param string $fname Calling function name
1078          *
1079          * @return array
1080          */
1081         function listTables( $prefix = null, $fname = __METHOD__ ) {
1082                 $result = $this->select(
1083                         'sqlite_master',
1084                         'name',
1085                         "type='table'"
1086                 );
1087
1088                 $endArray = [];
1089
1090                 foreach ( $result as $table ) {
1091                         $vars = get_object_vars( $table );
1092                         $table = array_pop( $vars );
1093
1094                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1095                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1096                                         $endArray[] = $table;
1097                                 }
1098                         }
1099                 }
1100
1101                 return $endArray;
1102         }
1103
1104         /**
1105          * Override due to no CASCADE support
1106          *
1107          * @param string $tableName
1108          * @param string $fName
1109          * @return bool|IResultWrapper
1110          * @throws DBReadOnlyError
1111          */
1112         public function dropTable( $tableName, $fName = __METHOD__ ) {
1113                 if ( !$this->tableExists( $tableName, $fName ) ) {
1114                         return false;
1115                 }
1116                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1117
1118                 return $this->query( $sql, $fName, self::QUERY_IGNORE_DBO_TRX );
1119         }
1120
1121         public function setTableAliases( array $aliases ) {
1122                 parent::setTableAliases( $aliases );
1123                 if ( $this->isOpen() ) {
1124                         $this->attachDatabasesFromTableAliases();
1125                 }
1126         }
1127
1128         /**
1129          * Issue ATTATCH statements for all unattached foreign DBs in table aliases
1130          */
1131         private function attachDatabasesFromTableAliases() {
1132                 foreach ( $this->tableAliases as $params ) {
1133                         if (
1134                                 $params['dbname'] !== $this->getDBname() &&
1135                                 !isset( $this->sessionAttachedDbs[$params['dbname']] )
1136                         ) {
1137                                 $this->attachDatabase( $params['dbname'] );
1138                                 $this->sessionAttachedDbs[$params['dbname']] = true;
1139                         }
1140                 }
1141         }
1142
1143         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1144                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1145                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1146                 $this->query(
1147                         "DELETE FROM $encTable WHERE name = $encName",
1148                         $fname,
1149                         self::QUERY_IGNORE_DBO_TRX
1150                 );
1151         }
1152
1153         public function databasesAreIndependent() {
1154                 return true;
1155         }
1156
1157         protected function doHandleSessionLossPreconnect() {
1158                 $this->sessionAttachedDbs = [];
1159         }
1160
1161         /**
1162          * @return PDO
1163          */
1164         protected function getBindingHandle() {
1165                 return parent::getBindingHandle();
1166         }
1167 }
1168
1169 /**
1170  * @deprecated since 1.29
1171  */
1172 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );