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
 172                 if ( $schema !== null ) {
 173                         throw new DBExpectedError( $this, __CLASS__ . ": domain schemas are not supported." );
 174                 }
 175
 176                 $fileName = self::generateFileName( $this->dbDir, $dbName );
 177                 if ( !is_readable( $fileName ) ) {
 178                         $error = "SQLite database file not readable";
 179                         $this->connLogger->error(
 180                                 "Error connecting to {db_server}: {error}",
 181                                 $this->getLogContext( [ 'method' => __METHOD__, 'error' => $error ] )
 182                         );
 183                         throw new DBConnectionError( $this, $error );
 184                 }
 185
 186                 // Only $dbName is used, the other parameters are irrelevant for SQLite databases
 187                 $this->openFile( $fileName, $dbName, $tablePrefix );
 188         }
 189
 190         /**
 191          * Opens a database file
 192          *
 193          * @param string $fileName
 194          * @param string $dbName
 195          * @param string $tablePrefix
 196          * @throws DBConnectionError
 197          */
 198         protected function openFile( $fileName, $dbName, $tablePrefix ) {
 199                 $this->dbPath = $fileName;
 200                 try {
 201                         $this->conn = new PDO(
 202                                 "sqlite:$fileName",
 203                                 '',
 204                                 '',
 205                                 [ PDO::ATTR_PERSISTENT => (bool)( $this->flags & self::DBO_PERSISTENT ) ]
 206                         );
 207                         $error = 'unknown error';
 208                 } catch ( PDOException $e ) {
 209                         $error = $e->getMessage();
 210                 }
 211
 212                 if ( !$this->conn ) {
 213                         $this->connLogger->error(
 214                                 "Error connecting to {db_server}: {error}",
 215                                 $this->getLogContext( [ 'method' => __METHOD__, 'error' => $error ] )
 216                         );
 217                         throw new DBConnectionError( $this, $error );
 218                 }
 219
 220                 try {
 221                         // Set error codes only, don't raise exceptions
 222                         $this->conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 223
 224                         $this->currentDomain = new DatabaseDomain( $dbName, null, $tablePrefix );
 225
 226                         $flags = self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY;
 227                         // Enforce LIKE to be case sensitive, just like MySQL
 228                         $this->query( 'PRAGMA case_sensitive_like = 1', __METHOD__, $flags );
 229                         // Apply an optimizations or requirements regarding fsync() usage
 230                         $sync = $this->connectionVariables['synchronous'] ?? null;
 231                         if ( in_array( $sync, [ 'EXTRA', 'FULL', 'NORMAL', 'OFF' ], true ) ) {
 232                                 $this->query( "PRAGMA synchronous = $sync", __METHOD__ );
 233                         }
 234                 } catch ( Exception $e ) {
 235                         // Connection was not fully initialized and is not safe for use
 236                         $this->conn = false;
 237                         throw $e;
 238                 }
 239         }
 240
 241         /**
 242          * @return string SQLite DB file path
 243          * @since 1.25
 244          */
 245         public function getDbFilePath() {
 246                 return $this->dbPath;
 247         }
 248
 249         /**
 250          * Does not actually close the connection, just destroys the reference for GC to do its work
 251          * @return bool
 252          */
 253         protected function closeConnection() {
 254                 $this->conn = null;
 255
 256                 return true;
 257         }
 258
 259         /**
 260          * Generates a database file name. Explicitly public for installer.
 261          * @param string $dir Directory where database resides
 262          * @param string $dbName Database name
 263          * @return string
 264          */
 265         public static function generateFileName( $dir, $dbName ) {
 266                 return "$dir/$dbName.sqlite";
 267         }
 268
 269         /**
 270          * Check if the searchindext table is FTS enabled.
 271          * @return bool False if not enabled.
 272          */
 273         public function checkForEnabledSearch() {
 274                 if ( self::$fulltextEnabled === null ) {
 275                         self::$fulltextEnabled = false;
 276                         $table = $this->tableName( 'searchindex' );
 277                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 278                         if ( $res ) {
 279                                 $row = $res->fetchRow();
 280                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 281                         }
 282                 }
 283
 284                 return self::$fulltextEnabled;
 285         }
 286
 287         /**
 288          * Returns version of currently supported SQLite fulltext search module or false if none present.
 289          * @return string
 290          */
 291         static function getFulltextSearchModule() {
 292                 static $cachedResult = null;
 293                 if ( $cachedResult !== null ) {
 294                         return $cachedResult;
 295                 }
 296                 $cachedResult = false;
 297                 $table = 'dummy_search_test';
 298
 299                 $db = self::newStandaloneInstance( ':memory:' );
 300                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 301                         $cachedResult = 'FTS3';
 302                 }
 303                 $db->close();
 304
 305                 return $cachedResult;
 306         }
 307
 308         /**
 309          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 310          * for details.
 311          *
 312          * @param string $name Database name to be used in queries like
 313          *   SELECT foo FROM dbname.table
 314          * @param bool|string $file Database file name. If omitted, will be generated
 315          *   using $name and configured data directory
 316          * @param string $fname Calling function name
 317          * @return IResultWrapper
 318          */
 319         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 320                 if ( !$file ) {
 321                         $file = self::generateFileName( $this->dbDir, $name );
 322                 }
 323                 $file = $this->addQuotes( $file );
 324
 325                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 326         }
 327
 328         protected function isWriteQuery( $sql ) {
 329                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 330         }
 331
 332         protected function isTransactableQuery( $sql ) {
 333                 return parent::isTransactableQuery( $sql ) && !in_array(
 334                         $this->getQueryVerb( $sql ),
 335                         [ 'ATTACH', 'PRAGMA' ],
 336                         true
 337                 );
 338         }
 339
 340         /**
 341          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 342          *
 343          * @param string $sql
 344          * @return bool|IResultWrapper
 345          */
 346         protected function doQuery( $sql ) {
 347                 $res = $this->getBindingHandle()->query( $sql );
 348                 if ( $res === false ) {
 349                         return false;
 350                 }
 351
 352                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 353                 $this->lastAffectedRowCount = $r->rowCount();
 354                 $res = new ResultWrapper( $this, $r->fetchAll() );
 355
 356                 return $res;
 357         }
 358
 359         /**
 360          * @param IResultWrapper|mixed $res
 361          */
 362         function freeResult( $res ) {
 363                 if ( $res instanceof ResultWrapper ) {
 364                         $res->result = null;
 365                 } else {
 366                         $res = null;
 367                 }
 368         }
 369
 370         /**
 371          * @param IResultWrapper|array $res
 372          * @return stdClass|bool
 373          */
 374         function fetchObject( $res ) {
 375                 if ( $res instanceof ResultWrapper ) {
 376                         $r =& $res->result;
 377                 } else {
 378                         $r =& $res;
 379                 }
 380
 381                 $cur = current( $r );
 382                 if ( is_array( $cur ) ) {
 383                         next( $r );
 384                         $obj = new stdClass;
 385                         foreach ( $cur as $k => $v ) {
 386                                 if ( !is_numeric( $k ) ) {
 387                                         $obj->$k = $v;
 388                                 }
 389                         }
 390
 391                         return $obj;
 392                 }
 393
 394                 return false;
 395         }
 396
 397         /**
 398          * @param IResultWrapper|mixed $res
 399          * @return array|bool
 400          */
 401         function fetchRow( $res ) {
 402                 if ( $res instanceof ResultWrapper ) {
 403                         $r =& $res->result;
 404                 } else {
 405                         $r =& $res;
 406                 }
 407                 $cur = current( $r );
 408                 if ( is_array( $cur ) ) {
 409                         next( $r );
 410
 411                         return $cur;
 412                 }
 413
 414                 return false;
 415         }
 416
 417         /**
 418          * The PDO::Statement class implements the array interface so count() will work
 419          *
 420          * @param IResultWrapper|array|false $res
 421          * @return int
 422          */
 423         function numRows( $res ) {
 424                 // false does not implement Countable
 425                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 426
 427                 return is_array( $r ) ? count( $r ) : 0;
 428         }
 429
 430         /**
 431          * @param IResultWrapper $res
 432          * @return int
 433          */
 434         function numFields( $res ) {
 435                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 436                 if ( is_array( $r ) && count( $r ) > 0 ) {
 437                         // The size of the result array is twice the number of fields. (T67578)
 438                         return count( $r[0] ) / 2;
 439                 } else {
 440                         // If the result is empty return 0
 441                         return 0;
 442                 }
 443         }
 444
 445         /**
 446          * @param IResultWrapper $res
 447          * @param int $n
 448          * @return bool
 449          */
 450         function fieldName( $res, $n ) {
 451                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 452                 if ( is_array( $r ) ) {
 453                         $keys = array_keys( $r[0] );
 454
 455                         return $keys[$n];
 456                 }
 457
 458                 return false;
 459         }
 460
 461         /**
 462          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 463          *
 464          * @param string $name
 465          * @param string $format
 466          * @return string
 467          */
 468         function tableName( $name, $format = 'quoted' ) {
 469                 // table names starting with sqlite_ are reserved
 470                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 471                         return $name;
 472                 }
 473
 474                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 475         }
 476
 477         /**
 478          * This must be called after nextSequenceVal
 479          *
 480          * @return int
 481          */
 482         function insertId() {
 483                 // PDO::lastInsertId yields a string :(
 484                 return intval( $this->getBindingHandle()->lastInsertId() );
 485         }
 486
 487         /**
 488          * @param IResultWrapper|array $res
 489          * @param int $row
 490          */
 491         function dataSeek( $res, $row ) {
 492                 if ( $res instanceof ResultWrapper ) {
 493                         $r =& $res->result;
 494                 } else {
 495                         $r =& $res;
 496                 }
 497                 reset( $r );
 498                 if ( $row > 0 ) {
 499                         for ( $i = 0; $i < $row; $i++ ) {
 500                                 next( $r );
 501                         }
 502                 }
 503         }
 504
 505         /**
 506          * @return string
 507          */
 508         function lastError() {
 509                 if ( !is_object( $this->conn ) ) {
 510                         return "Cannot return last error, no db connection";
 511                 }
 512                 $e = $this->conn->errorInfo();
 513
 514                 return $e[2] ?? '';
 515         }
 516
 517         /**
 518          * @return string
 519          */
 520         function lastErrno() {
 521                 if ( !is_object( $this->conn ) ) {
 522                         return "Cannot return last error, no db connection";
 523                 } else {
 524                         $info = $this->conn->errorInfo();
 525
 526                         return $info[1];
 527                 }
 528         }
 529
 530         /**
 531          * @return int
 532          */
 533         protected function fetchAffectedRowCount() {
 534                 return $this->lastAffectedRowCount;
 535         }
 536
 537         function tableExists( $table, $fname = __METHOD__ ) {
 538                 $tableRaw = $this->tableName( $table, 'raw' );
 539                 if ( isset( $this->sessionTempTables[$tableRaw] ) ) {
 540                         return true; // already known to exist
 541                 }
 542
 543                 $encTable = $this->addQuotes( $tableRaw );
 544                 $res = $this->query(
 545                         "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable" );
 546
 547                 return $res->numRows() ? true : false;
 548         }
 549
 550         /**
 551          * Returns information about an index
 552          * Returns false if the index does not exist
 553          * - if errors are explicitly ignored, returns NULL on failure
 554          *
 555          * @param string $table
 556          * @param string $index
 557          * @param string $fname
 558          * @return array|false
 559          */
 560         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 561                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 562                 $res = $this->query( $sql, $fname );
 563                 if ( !$res || $res->numRows() == 0 ) {
 564                         return false;
 565                 }
 566                 $info = [];
 567                 foreach ( $res as $row ) {
 568                         $info[] = $row->name;
 569                 }
 570
 571                 return $info;
 572         }
 573
 574         /**
 575          * @param string $table
 576          * @param string $index
 577          * @param string $fname
 578          * @return bool|null
 579          */
 580         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 581                 $row = $this->selectRow( 'sqlite_master', '*',
 582                         [
 583                                 'type' => 'index',
 584                                 'name' => $this->indexName( $index ),
 585                         ], $fname );
 586                 if ( !$row || !isset( $row->sql ) ) {
 587                         return null;
 588                 }
 589
 590                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 591                 $indexPos = strpos( $row->sql, 'INDEX' );
 592                 if ( $indexPos === false ) {
 593                         return null;
 594                 }
 595                 $firstPart = substr( $row->sql, 0, $indexPos );
 596                 $options = explode( ' ', $firstPart );
 597
 598                 return in_array( 'UNIQUE', $options );
 599         }
 600
 601         /**
 602          * Filter the options used in SELECT statements
 603          *
 604          * @param array $options
 605          * @return array
 606          */
 607         function makeSelectOptions( $options ) {
 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         /**
 776          * @return string Wikitext of a link to the server software's web site
 777          */
 778         public function getSoftwareLink() {
 779                 return "[{{int:version-db-sqlite-url}} SQLite]";
 780         }
 781
 782         /**
 783          * @return string Version information from the database
 784          */
 785         function getServerVersion() {
 786                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 787
 788                 return $ver;
 789         }
 790
 791         /**
 792          * Get information about a given field
 793          * Returns false if the field does not exist.
 794          *
 795          * @param string $table
 796          * @param string $field
 797          * @return SQLiteField|bool False on failure
 798          */
 799         function fieldInfo( $table, $field ) {
 800                 $tableName = $this->tableName( $table );
 801                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 802                 $res = $this->query( $sql, __METHOD__ );
 803                 foreach ( $res as $row ) {
 804                         if ( $row->name == $field ) {
 805                                 return new SQLiteField( $row, $tableName );
 806                         }
 807                 }
 808
 809                 return false;
 810         }
 811
 812         protected function doBegin( $fname = '' ) {
 813                 if ( $this->trxMode ) {
 814                         $this->query( "BEGIN {$this->trxMode}", $fname );
 815                 } else {
 816                         $this->query( 'BEGIN', $fname );
 817                 }
 818                 $this->trxLevel = 1;
 819         }
 820
 821         /**
 822          * @param string $s
 823          * @return string
 824          */
 825         function strencode( $s ) {
 826                 return substr( $this->addQuotes( $s ), 1, -1 );
 827         }
 828
 829         /**
 830          * @param string $b
 831          * @return Blob
 832          */
 833         function encodeBlob( $b ) {
 834                 return new Blob( $b );
 835         }
 836
 837         /**
 838          * @param Blob|string $b
 839          * @return string
 840          */
 841         function decodeBlob( $b ) {
 842                 if ( $b instanceof Blob ) {
 843                         $b = $b->fetch();
 844                 }
 845
 846                 return $b;
 847         }
 848
 849         /**
 850          * @param string|int|null|bool|Blob $s
 851          * @return string|int
 852          */
 853         function addQuotes( $s ) {
 854                 if ( $s instanceof Blob ) {
 855                         return "x'" . bin2hex( $s->fetch() ) . "'";
 856                 } elseif ( is_bool( $s ) ) {
 857                         return (int)$s;
 858                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 859                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 860                         // This is a known limitation of SQLite's mprintf function which PDO
 861                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 862                         // https://bugs.php.net/bug.php?id=63419
 863                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 864                         // https://bugs.php.net/bug.php?id=62361
 865                         // There is an additional bug regarding sorting this data after insert
 866                         // on older versions of sqlite shipped with ubuntu 12.04
 867                         // https://phabricator.wikimedia.org/T74367
 868                         $this->queryLogger->debug(
 869                                 __FUNCTION__ .
 870                                 ': Quoting value containing null byte. ' .
 871                                 'For consistency all binary data should have been ' .
 872                                 'first processed with self::encodeBlob()'
 873                         );
 874                         return "x'" . bin2hex( (string)$s ) . "'";
 875                 } else {
 876                         return $this->getBindingHandle()->quote( (string)$s );
 877                 }
 878         }
 879
 880         public function buildSubstring( $input, $startPosition, $length = null ) {
 881                 $this->assertBuildSubstringParams( $startPosition, $length );
 882                 $params = [ $input, $startPosition ];
 883                 if ( $length !== null ) {
 884                         $params[] = $length;
 885                 }
 886                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 887         }
 888
 889         /**
 890          * @param string $field Field or column to cast
 891          * @return string
 892          * @since 1.28
 893          */
 894         public function buildStringCast( $field ) {
 895                 return 'CAST ( ' . $field . ' AS TEXT )';
 896         }
 897
 898         /**
 899          * No-op version of deadlockLoop
 900          *
 901          * @return mixed
 902          */
 903         public function deadlockLoop( /*...*/ ) {
 904                 $args = func_get_args();
 905                 $function = array_shift( $args );
 906
 907                 return $function( ...$args );
 908         }
 909
 910         /**
 911          * @param string $s
 912          * @return string
 913          */
 914         protected function replaceVars( $s ) {
 915                 $s = parent::replaceVars( $s );
 916                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 917                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 918
 919                         // binary/varbinary column type -> blob
 920                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 921                         // no such thing as unsigned
 922                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 923                         // INT -> INTEGER
 924                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 925                         // floating point types -> REAL
 926                         $s = preg_replace(
 927                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 928                                 'REAL',
 929                                 $s
 930                         );
 931                         // varchar -> TEXT
 932                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 933                         // TEXT normalization
 934                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 935                         // BLOB normalization
 936                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 937                         // BOOL -> INTEGER
 938                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 939                         // DATETIME -> TEXT
 940                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 941                         // No ENUM type
 942                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 943                         // binary collation type -> nothing
 944                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 945                         // auto_increment -> autoincrement
 946                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 947                         // No explicit options
 948                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 949                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 950                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 951                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 952                         // No truncated indexes
 953                         $s = preg_replace( '/\(\d+\)/', '', $s );
 954                         // No FULLTEXT
 955                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 956                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 957                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 958                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 959                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 960                         // INSERT IGNORE --> INSERT OR IGNORE
 961                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 962                 }
 963
 964                 return $s;
 965         }
 966
 967         public function lock( $lockName, $method, $timeout = 5 ) {
 968                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 969                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 970                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 971                         }
 972                 }
 973
 974                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 975         }
 976
 977         public function unlock( $lockName, $method ) {
 978                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 979         }
 980
 981         /**
 982          * Build a concatenation list to feed into a SQL query
 983          *
 984          * @param string[] $stringList
 985          * @return string
 986          */
 987         function buildConcat( $stringList ) {
 988                 return '(' . implode( ') || (', $stringList ) . ')';
 989         }
 990
 991         public function buildGroupConcatField(
 992                 $delim, $table, $field, $conds = '', $join_conds = []
 993         ) {
 994                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 995
 996                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 997         }
 998
 999         /**
1000          * @param string $oldName
1001          * @param string $newName
1002          * @param bool $temporary
1003          * @param string $fname
1004          * @return bool|IResultWrapper
1005          * @throws RuntimeException
1006          */
1007         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1008                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
1009                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
1010                 $obj = $this->fetchObject( $res );
1011                 if ( !$obj ) {
1012                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
1013                 }
1014                 $sql = $obj->sql;
1015                 $sql = preg_replace(
1016                         '/(?<=\W)"?' .
1017                                 preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ), '/' ) .
1018                                 '"?(?=\W)/',
1019                         $this->addIdentifierQuotes( $newName ),
1020                         $sql,
1021                         1
1022                 );
1023                 if ( $temporary ) {
1024                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
1025                                 $this->queryLogger->debug(
1026                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
1027                         } else {
1028                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
1029                         }
1030                 }
1031
1032                 $res = $this->query( $sql, $fname, self::QUERY_PSEUDO_PERMANENT );
1033
1034                 // Take over indexes
1035                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
1036                 foreach ( $indexList as $index ) {
1037                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
1038                                 continue;
1039                         }
1040
1041                         if ( $index->unique ) {
1042                                 $sql = 'CREATE UNIQUE INDEX';
1043                         } else {
1044                                 $sql = 'CREATE INDEX';
1045                         }
1046                         // Try to come up with a new index name, given indexes have database scope in SQLite
1047                         $indexName = $newName . '_' . $index->name;
1048                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1049
1050                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1051                         $fields = [];
1052                         foreach ( $indexInfo as $indexInfoRow ) {
1053                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1054                         }
1055
1056                         $sql .= '(' . implode( ',', $fields ) . ')';
1057
1058                         $this->query( $sql );
1059                 }
1060
1061                 return $res;
1062         }
1063
1064         /**
1065          * List all tables on the database
1066          *
1067          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1068          * @param string $fname Calling function name
1069          *
1070          * @return array
1071          */
1072         function listTables( $prefix = null, $fname = __METHOD__ ) {
1073                 $result = $this->select(
1074                         'sqlite_master',
1075                         'name',
1076                         "type='table'"
1077                 );
1078
1079                 $endArray = [];
1080
1081                 foreach ( $result as $table ) {
1082                         $vars = get_object_vars( $table );
1083                         $table = array_pop( $vars );
1084
1085                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1086                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1087                                         $endArray[] = $table;
1088                                 }
1089                         }
1090                 }
1091
1092                 return $endArray;
1093         }
1094
1095         /**
1096          * Override due to no CASCADE support
1097          *
1098          * @param string $tableName
1099          * @param string $fName
1100          * @return bool|IResultWrapper
1101          * @throws DBReadOnlyError
1102          */
1103         public function dropTable( $tableName, $fName = __METHOD__ ) {
1104                 if ( !$this->tableExists( $tableName, $fName ) ) {
1105                         return false;
1106                 }
1107                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1108
1109                 return $this->query( $sql, $fName );
1110         }
1111
1112         public function setTableAliases( array $aliases ) {
1113                 parent::setTableAliases( $aliases );
1114                 foreach ( $this->tableAliases as $params ) {
1115                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1116                                 continue;
1117                         }
1118                         $this->attachDatabase( $params['dbname'] );
1119                         $this->alreadyAttached[$params['dbname']] = true;
1120                 }
1121         }
1122
1123         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1124                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1125                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1126                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1127         }
1128
1129         public function databasesAreIndependent() {
1130                 return true;
1131         }
1132
1133         /**
1134          * @return PDO
1135          */
1136         protected function getBindingHandle() {
1137                 return parent::getBindingHandle();
1138         }
1139 }
1140
1141 /**
1142  * @deprecated since 1.29
1143  */
1144 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );