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