includes/db/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 class PostgresField implements Field {
  25         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname,
  26                 $has_default, $default;
  27
  28         /**
  29          * @param DatabaseBase $db
  30          * @param string $table
  31          * @param string $field
  32          * @return null|PostgresField
  33          */
  34         static function fromText( $db, $table, $field ) {
  35                 $q = <<<SQL
  36 SELECT
  37  attnotnull, attlen, conname AS conname,
  38  atthasdef,
  39  adsrc,
  40  COALESCE(condeferred, 'f') AS deferred,
  41  COALESCE(condeferrable, 'f') AS deferrable,
  42  CASE WHEN typname = 'int2' THEN 'smallint'
  43   WHEN typname = 'int4' THEN 'integer'
  44   WHEN typname = 'int8' THEN 'bigint'
  45   WHEN typname = 'bpchar' THEN 'char'
  46  ELSE typname END AS typname
  47 FROM pg_class c
  48 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  49 JOIN pg_attribute a ON (a.attrelid = c.oid)
  50 JOIN pg_type t ON (t.oid = a.atttypid)
  51 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  52 LEFT JOIN pg_attrdef d on c.oid=d.adrelid and a.attnum=d.adnum
  53 WHERE relkind = 'r'
  54 AND nspname=%s
  55 AND relname=%s
  56 AND attname=%s;
  57 SQL;
  58
  59                 $table = $db->tableName( $table, 'raw' );
  60                 $res = $db->query(
  61                         sprintf( $q,
  62                                 $db->addQuotes( $db->getCoreSchema() ),
  63                                 $db->addQuotes( $table ),
  64                                 $db->addQuotes( $field )
  65                         )
  66                 );
  67                 $row = $db->fetchObject( $res );
  68                 if ( !$row ) {
  69                         return null;
  70                 }
  71                 $n = new PostgresField;
  72                 $n->type = $row->typname;
  73                 $n->nullable = ( $row->attnotnull == 'f' );
  74                 $n->name = $field;
  75                 $n->tablename = $table;
  76                 $n->max_length = $row->attlen;
  77                 $n->deferrable = ( $row->deferrable == 't' );
  78                 $n->deferred = ( $row->deferred == 't' );
  79                 $n->conname = $row->conname;
  80                 $n->has_default = ( $row->atthasdef === 't' );
  81                 $n->default = $row->adsrc;
  82
  83                 return $n;
  84         }
  85
  86         function name() {
  87                 return $this->name;
  88         }
  89
  90         function tableName() {
  91                 return $this->tablename;
  92         }
  93
  94         function type() {
  95                 return $this->type;
  96         }
  97
  98         function isNullable() {
  99                 return $this->nullable;
 100         }
 101
 102         function maxLength() {
 103                 return $this->max_length;
 104         }
 105
 106         function is_deferrable() {
 107                 return $this->deferrable;
 108         }
 109
 110         function is_deferred() {
 111                 return $this->deferred;
 112         }
 113
 114         function conname() {
 115                 return $this->conname;
 116         }
 117
 118         /**
 119          * @since 1.19
 120          * @return bool|mixed
 121          */
 122         function defaultValue() {
 123                 if ( $this->has_default ) {
 124                         return $this->default;
 125                 } else {
 126                         return false;
 127                 }
 128         }
 129 }
 130
 131 /**
 132  * Manage savepoints within a transaction
 133  * @ingroup Database
 134  * @since 1.19
 135  */
 136 class SavepointPostgres {
 137         /** @var DatabasePostgres Establish a savepoint within a transaction */
 138         protected $dbw;
 139         protected $id;
 140         protected $didbegin;
 141
 142         /**
 143          * @param DatabaseBase $dbw
 144          * @param int $id
 145          */
 146         public function __construct( $dbw, $id ) {
 147                 $this->dbw = $dbw;
 148                 $this->id = $id;
 149                 $this->didbegin = false;
 150                 /* If we are not in a transaction, we need to be for savepoint trickery */
 151                 if ( !$dbw->trxLevel() ) {
 152                         $dbw->begin( "FOR SAVEPOINT", DatabasePostgres::TRANSACTION_INTERNAL );
 153                         $this->didbegin = true;
 154                 }
 155         }
 156
 157         public function __destruct() {
 158                 if ( $this->didbegin ) {
 159                         $this->dbw->rollback();
 160                         $this->didbegin = false;
 161                 }
 162         }
 163
 164         public function commit() {
 165                 if ( $this->didbegin ) {
 166                         $this->dbw->commit();
 167                         $this->didbegin = false;
 168                 }
 169         }
 170
 171         protected function query( $keyword, $msg_ok, $msg_failed ) {
 172                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 173                 } else {
 174                         wfDebug( sprintf( $msg_failed, $this->id ) );
 175                 }
 176         }
 177
 178         public function savepoint() {
 179                 $this->query( "SAVEPOINT",
 180                         "Transaction state: savepoint \"%s\" established.\n",
 181                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 182                 );
 183         }
 184
 185         public function release() {
 186                 $this->query( "RELEASE",
 187                         "Transaction state: savepoint \"%s\" released.\n",
 188                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 189                 );
 190         }
 191
 192         public function rollback() {
 193                 $this->query( "ROLLBACK TO",
 194                         "Transaction state: savepoint \"%s\" rolled back.\n",
 195                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 196                 );
 197         }
 198
 199         public function __toString() {
 200                 return (string)$this->id;
 201         }
 202 }
 203
 204 /**
 205  * @ingroup Database
 206  */
 207 class DatabasePostgres extends Database {
 208         /** @var resource */
 209         protected $mLastResult = null;
 210
 211         /** @var int The number of rows affected as an integer */
 212         protected $mAffectedRows = null;
 213
 214         /** @var int */
 215         private $mInsertId = null;
 216
 217         /** @var float|string */
 218         private $numericVersion = null;
 219
 220         /** @var string Connect string to open a PostgreSQL connection */
 221         private $connectString;
 222
 223         /** @var string */
 224         private $mCoreSchema;
 225
 226         function getType() {
 227                 return 'postgres';
 228         }
 229
 230         function cascadingDeletes() {
 231                 return true;
 232         }
 233
 234         function cleanupTriggers() {
 235                 return true;
 236         }
 237
 238         function strictIPs() {
 239                 return true;
 240         }
 241
 242         function realTimestamps() {
 243                 return true;
 244         }
 245
 246         function implicitGroupby() {
 247                 return false;
 248         }
 249
 250         function implicitOrderby() {
 251                 return false;
 252         }
 253
 254         function searchableIPs() {
 255                 return true;
 256         }
 257
 258         function functionalIndexes() {
 259                 return true;
 260         }
 261
 262         function hasConstraint( $name ) {
 263                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 264                         "WHERE c.connamespace = n.oid AND conname = '" .
 265                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 266                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 267                 $res = $this->doQuery( $sql );
 268
 269                 return $this->numRows( $res );
 270         }
 271
 272         /**
 273          * Usually aborts on failure
 274          * @param string $server
 275          * @param string $user
 276          * @param string $password
 277          * @param string $dbName
 278          * @throws DBConnectionError|Exception
 279          * @return DatabaseBase|null
 280          */
 281         function open( $server, $user, $password, $dbName ) {
 282                 # Test for Postgres support, to avoid suppressed fatal error
 283                 if ( !function_exists( 'pg_connect' ) ) {
 284                         throw new DBConnectionError(
 285                                 $this,
 286                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 287                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 288                                 "webserver and database)\n"
 289                         );
 290                 }
 291
 292                 global $wgDBport;
 293
 294                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 295                         return null;
 296                 }
 297
 298                 $this->mServer = $server;
 299                 $port = $wgDBport;
 300                 $this->mUser = $user;
 301                 $this->mPassword = $password;
 302                 $this->mDBname = $dbName;
 303
 304                 $connectVars = [
 305                         'dbname' => $dbName,
 306                         'user' => $user,
 307                         'password' => $password
 308                 ];
 309                 if ( $server != false && $server != '' ) {
 310                         $connectVars['host'] = $server;
 311                 }
 312                 if ( $port != false && $port != '' ) {
 313                         $connectVars['port'] = $port;
 314                 }
 315                 if ( $this->mFlags & DBO_SSL ) {
 316                         $connectVars['sslmode'] = 1;
 317                 }
 318
 319                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 320                 $this->close();
 321                 $this->installErrorHandler();
 322
 323                 try {
 324                         $this->mConn = pg_connect( $this->connectString );
 325                 } catch ( Exception $ex ) {
 326                         $this->restoreErrorHandler();
 327                         throw $ex;
 328                 }
 329
 330                 $phpError = $this->restoreErrorHandler();
 331
 332                 if ( !$this->mConn ) {
 333                         wfDebug( "DB connection error\n" );
 334                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 335                                 substr( $password, 0, 3 ) . "...\n" );
 336                         wfDebug( $this->lastError() . "\n" );
 337                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 338                 }
 339
 340                 $this->mOpened = true;
 341
 342                 global $wgCommandLineMode;
 343                 # If called from the command-line (e.g. importDump), only show errors
 344                 if ( $wgCommandLineMode ) {
 345                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 346                 }
 347
 348                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 349                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 350                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 351                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 352                 if ( $this->getServerVersion() >= 9.0 ) {
 353                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 354                 }
 355
 356                 global $wgDBmwschema;
 357                 $this->determineCoreSchema( $wgDBmwschema );
 358
 359                 return $this->mConn;
 360         }
 361
 362         /**
 363          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 364          * DB name doesn't match the open connection, open a new one
 365          * @param string $db
 366          * @return bool
 367          */
 368         function selectDB( $db ) {
 369                 if ( $this->mDBname !== $db ) {
 370                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 371                 } else {
 372                         return true;
 373                 }
 374         }
 375
 376         function makeConnectionString( $vars ) {
 377                 $s = '';
 378                 foreach ( $vars as $name => $value ) {
 379                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 380                 }
 381
 382                 return $s;
 383         }
 384
 385         /**
 386          * Closes a database connection, if it is open
 387          * Returns success, true if already closed
 388          * @return bool
 389          */
 390         protected function closeConnection() {
 391                 return pg_close( $this->mConn );
 392         }
 393
 394         public function doQuery( $sql ) {
 395                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 396                 // Clear previously left over PQresult
 397                 while ( $res = pg_get_result( $this->mConn ) ) {
 398                         pg_free_result( $res );
 399                 }
 400                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 401                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 402                 }
 403                 $this->mLastResult = pg_get_result( $this->mConn );
 404                 $this->mAffectedRows = null;
 405                 if ( pg_result_error( $this->mLastResult ) ) {
 406                         return false;
 407                 }
 408
 409                 return $this->mLastResult;
 410         }
 411
 412         protected function dumpError() {
 413                 $diags = [
 414                         PGSQL_DIAG_SEVERITY,
 415                         PGSQL_DIAG_SQLSTATE,
 416                         PGSQL_DIAG_MESSAGE_PRIMARY,
 417                         PGSQL_DIAG_MESSAGE_DETAIL,
 418                         PGSQL_DIAG_MESSAGE_HINT,
 419                         PGSQL_DIAG_STATEMENT_POSITION,
 420                         PGSQL_DIAG_INTERNAL_POSITION,
 421                         PGSQL_DIAG_INTERNAL_QUERY,
 422                         PGSQL_DIAG_CONTEXT,
 423                         PGSQL_DIAG_SOURCE_FILE,
 424                         PGSQL_DIAG_SOURCE_LINE,
 425                         PGSQL_DIAG_SOURCE_FUNCTION
 426                 ];
 427                 foreach ( $diags as $d ) {
 428                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 429                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 430                 }
 431         }
 432
 433         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 434                 if ( $tempIgnore ) {
 435                         /* Check for constraint violation */
 436                         if ( $errno === '23505' ) {
 437                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 438
 439                                 return;
 440                         }
 441                 }
 442                 /* Transaction stays in the ERROR state until rolled back */
 443                 if ( $this->mTrxLevel ) {
 444                         $ignore = $this->ignoreErrors( true );
 445                         $this->rollback( __METHOD__ );
 446                         $this->ignoreErrors( $ignore );
 447                 }
 448                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 449         }
 450
 451         function queryIgnore( $sql, $fname = __METHOD__ ) {
 452                 return $this->query( $sql, $fname, true );
 453         }
 454
 455         /**
 456          * @param stdClass|ResultWrapper $res
 457          * @throws DBUnexpectedError
 458          */
 459         function freeResult( $res ) {
 460                 if ( $res instanceof ResultWrapper ) {
 461                         $res = $res->result;
 462                 }
 463                 MediaWiki\suppressWarnings();
 464                 $ok = pg_free_result( $res );
 465                 MediaWiki\restoreWarnings();
 466                 if ( !$ok ) {
 467                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 468                 }
 469         }
 470
 471         /**
 472          * @param ResultWrapper|stdClass $res
 473          * @return stdClass
 474          * @throws DBUnexpectedError
 475          */
 476         function fetchObject( $res ) {
 477                 if ( $res instanceof ResultWrapper ) {
 478                         $res = $res->result;
 479                 }
 480                 MediaWiki\suppressWarnings();
 481                 $row = pg_fetch_object( $res );
 482                 MediaWiki\restoreWarnings();
 483                 # @todo FIXME: HACK HACK HACK HACK debug
 484
 485                 # @todo hashar: not sure if the following test really trigger if the object
 486                 #          fetching failed.
 487                 if ( pg_last_error( $this->mConn ) ) {
 488                         throw new DBUnexpectedError(
 489                                 $this,
 490                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 491                         );
 492                 }
 493
 494                 return $row;
 495         }
 496
 497         function fetchRow( $res ) {
 498                 if ( $res instanceof ResultWrapper ) {
 499                         $res = $res->result;
 500                 }
 501                 MediaWiki\suppressWarnings();
 502                 $row = pg_fetch_array( $res );
 503                 MediaWiki\restoreWarnings();
 504                 if ( pg_last_error( $this->mConn ) ) {
 505                         throw new DBUnexpectedError(
 506                                 $this,
 507                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 508                         );
 509                 }
 510
 511                 return $row;
 512         }
 513
 514         function numRows( $res ) {
 515                 if ( $res instanceof ResultWrapper ) {
 516                         $res = $res->result;
 517                 }
 518                 MediaWiki\suppressWarnings();
 519                 $n = pg_num_rows( $res );
 520                 MediaWiki\restoreWarnings();
 521                 if ( pg_last_error( $this->mConn ) ) {
 522                         throw new DBUnexpectedError(
 523                                 $this,
 524                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 525                         );
 526                 }
 527
 528                 return $n;
 529         }
 530
 531         function numFields( $res ) {
 532                 if ( $res instanceof ResultWrapper ) {
 533                         $res = $res->result;
 534                 }
 535
 536                 return pg_num_fields( $res );
 537         }
 538
 539         function fieldName( $res, $n ) {
 540                 if ( $res instanceof ResultWrapper ) {
 541                         $res = $res->result;
 542                 }
 543
 544                 return pg_field_name( $res, $n );
 545         }
 546
 547         /**
 548          * Return the result of the last call to nextSequenceValue();
 549          * This must be called after nextSequenceValue().
 550          *
 551          * @return int|null
 552          */
 553         function insertId() {
 554                 return $this->mInsertId;
 555         }
 556
 557         /**
 558          * @param mixed $res
 559          * @param int $row
 560          * @return bool
 561          */
 562         function dataSeek( $res, $row ) {
 563                 if ( $res instanceof ResultWrapper ) {
 564                         $res = $res->result;
 565                 }
 566
 567                 return pg_result_seek( $res, $row );
 568         }
 569
 570         function lastError() {
 571                 if ( $this->mConn ) {
 572                         if ( $this->mLastResult ) {
 573                                 return pg_result_error( $this->mLastResult );
 574                         } else {
 575                                 return pg_last_error();
 576                         }
 577                 } else {
 578                         return 'No database connection';
 579                 }
 580         }
 581
 582         function lastErrno() {
 583                 if ( $this->mLastResult ) {
 584                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 585                 } else {
 586                         return false;
 587                 }
 588         }
 589
 590         function affectedRows() {
 591                 if ( !is_null( $this->mAffectedRows ) ) {
 592                         // Forced result for simulated queries
 593                         return $this->mAffectedRows;
 594                 }
 595                 if ( empty( $this->mLastResult ) ) {
 596                         return 0;
 597                 }
 598
 599                 return pg_affected_rows( $this->mLastResult );
 600         }
 601
 602         /**
 603          * Estimate rows in dataset
 604          * Returns estimated count, based on EXPLAIN output
 605          * This is not necessarily an accurate estimate, so use sparingly
 606          * Returns -1 if count cannot be found
 607          * Takes same arguments as Database::select()
 608          *
 609          * @param string $table
 610          * @param string $vars
 611          * @param string $conds
 612          * @param string $fname
 613          * @param array $options
 614          * @return int
 615          */
 616         function estimateRowCount( $table, $vars = '*', $conds = '',
 617                 $fname = __METHOD__, $options = []
 618         ) {
 619                 $options['EXPLAIN'] = true;
 620                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 621                 $rows = -1;
 622                 if ( $res ) {
 623                         $row = $this->fetchRow( $res );
 624                         $count = [];
 625                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 626                                 $rows = (int)$count[1];
 627                         }
 628                 }
 629
 630                 return $rows;
 631         }
 632
 633         /**
 634          * Returns information about an index
 635          * If errors are explicitly ignored, returns NULL on failure
 636          *
 637          * @param string $table
 638          * @param string $index
 639          * @param string $fname
 640          * @return bool|null
 641          */
 642         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 643                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 644                 $res = $this->query( $sql, $fname );
 645                 if ( !$res ) {
 646                         return null;
 647                 }
 648                 foreach ( $res as $row ) {
 649                         if ( $row->indexname == $this->indexName( $index ) ) {
 650                                 return $row;
 651                         }
 652                 }
 653
 654                 return false;
 655         }
 656
 657         /**
 658          * Returns is of attributes used in index
 659          *
 660          * @since 1.19
 661          * @param string $index
 662          * @param bool|string $schema
 663          * @return array
 664          */
 665         function indexAttributes( $index, $schema = false ) {
 666                 if ( $schema === false ) {
 667                         $schema = $this->getCoreSchema();
 668                 }
 669                 /*
 670                  * A subquery would be not needed if we didn't care about the order
 671                  * of attributes, but we do
 672                  */
 673                 $sql = <<<__INDEXATTR__
 674
 675                         SELECT opcname,
 676                                 attname,
 677                                 i.indoption[s.g] as option,
 678                                 pg_am.amname
 679                         FROM
 680                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 681                                         FROM
 682                                                 pg_index isub
 683                                         JOIN pg_class cis
 684                                                 ON cis.oid=isub.indexrelid
 685                                         JOIN pg_namespace ns
 686                                                 ON cis.relnamespace = ns.oid
 687                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 688                                 pg_attribute,
 689                                 pg_opclass opcls,
 690                                 pg_am,
 691                                 pg_class ci
 692                                 JOIN pg_index i
 693                                         ON ci.oid=i.indexrelid
 694                                 JOIN pg_class ct
 695                                         ON ct.oid = i.indrelid
 696                                 JOIN pg_namespace n
 697                                         ON ci.relnamespace = n.oid
 698                                 WHERE
 699                                         ci.relname='$index' AND n.nspname='$schema'
 700                                         AND     attrelid = ct.oid
 701                                         AND     i.indkey[s.g] = attnum
 702                                         AND     i.indclass[s.g] = opcls.oid
 703                                         AND     pg_am.oid = opcls.opcmethod
 704 __INDEXATTR__;
 705                 $res = $this->query( $sql, __METHOD__ );
 706                 $a = [];
 707                 if ( $res ) {
 708                         foreach ( $res as $row ) {
 709                                 $a[] = [
 710                                         $row->attname,
 711                                         $row->opcname,
 712                                         $row->amname,
 713                                         $row->option ];
 714                         }
 715                 } else {
 716                         return null;
 717                 }
 718
 719                 return $a;
 720         }
 721
 722         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 723                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 724                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 725                         $this->strencode( $this->indexName( $index ) ) .
 726                         ")'";
 727                 $res = $this->query( $sql, $fname );
 728                 if ( !$res ) {
 729                         return null;
 730                 }
 731
 732                 return $res->numRows() > 0;
 733         }
 734
 735         /**
 736          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 737          * to the parent function to get the actual SQL text.
 738          *
 739          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 740          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 741          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 742          *
 743          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 744          * @see DatabaseBase::selectSQLText
 745          */
 746         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 747                 $options = [], $join_conds = []
 748         ) {
 749                 if ( is_array( $options ) ) {
 750                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 751                         if ( $forUpdateKey !== false && $join_conds ) {
 752                                 unset( $options[$forUpdateKey] );
 753
 754                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 755                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 756                                                 $options['FOR UPDATE'][] = $table_cond;
 757                                         }
 758                                 }
 759                         }
 760
 761                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 762                                 unset( $options['ORDER BY'] );
 763                         }
 764                 }
 765
 766                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 767         }
 768
 769         /**
 770          * INSERT wrapper, inserts an array into a table
 771          *
 772          * $args may be a single associative array, or an array of these with numeric keys,
 773          * for multi-row insert (Postgres version 8.2 and above only).
 774          *
 775          * @param string $table Name of the table to insert to.
 776          * @param array $args Items to insert into the table.
 777          * @param string $fname Name of the function, for profiling
 778          * @param array|string $options String or array. Valid options: IGNORE
 779          * @return bool Success of insert operation. IGNORE always returns true.
 780          */
 781         function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 782                 if ( !count( $args ) ) {
 783                         return true;
 784                 }
 785
 786                 $table = $this->tableName( $table );
 787                 if ( !isset( $this->numericVersion ) ) {
 788                         $this->getServerVersion();
 789                 }
 790
 791                 if ( !is_array( $options ) ) {
 792                         $options = [ $options ];
 793                 }
 794
 795                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 796                         $multi = true;
 797                         $keys = array_keys( $args[0] );
 798                 } else {
 799                         $multi = false;
 800                         $keys = array_keys( $args );
 801                 }
 802
 803                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 804                 $savepoint = null;
 805                 if ( in_array( 'IGNORE', $options ) ) {
 806                         $savepoint = new SavepointPostgres( $this, 'mw' );
 807                         $olde = error_reporting( 0 );
 808                         // For future use, we may want to track the number of actual inserts
 809                         // Right now, insert (all writes) simply return true/false
 810                         $numrowsinserted = 0;
 811                 }
 812
 813                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 814
 815                 if ( $multi ) {
 816                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 817                                 $first = true;
 818                                 foreach ( $args as $row ) {
 819                                         if ( $first ) {
 820                                                 $first = false;
 821                                         } else {
 822                                                 $sql .= ',';
 823                                         }
 824                                         $sql .= '(' . $this->makeList( $row ) . ')';
 825                                 }
 826                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 827                         } else {
 828                                 $res = true;
 829                                 $origsql = $sql;
 830                                 foreach ( $args as $row ) {
 831                                         $tempsql = $origsql;
 832                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 833
 834                                         if ( $savepoint ) {
 835                                                 $savepoint->savepoint();
 836                                         }
 837
 838                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 839
 840                                         if ( $savepoint ) {
 841                                                 $bar = pg_result_error( $this->mLastResult );
 842                                                 if ( $bar != false ) {
 843                                                         $savepoint->rollback();
 844                                                 } else {
 845                                                         $savepoint->release();
 846                                                         $numrowsinserted++;
 847                                                 }
 848                                         }
 849
 850                                         // If any of them fail, we fail overall for this function call
 851                                         // Note that this will be ignored if IGNORE is set
 852                                         if ( !$tempres ) {
 853                                                 $res = false;
 854                                         }
 855                                 }
 856                         }
 857                 } else {
 858                         // Not multi, just a lone insert
 859                         if ( $savepoint ) {
 860                                 $savepoint->savepoint();
 861                         }
 862
 863                         $sql .= '(' . $this->makeList( $args ) . ')';
 864                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 865                         if ( $savepoint ) {
 866                                 $bar = pg_result_error( $this->mLastResult );
 867                                 if ( $bar != false ) {
 868                                         $savepoint->rollback();
 869                                 } else {
 870                                         $savepoint->release();
 871                                         $numrowsinserted++;
 872                                 }
 873                         }
 874                 }
 875                 if ( $savepoint ) {
 876                         error_reporting( $olde );
 877                         $savepoint->commit();
 878
 879                         // Set the affected row count for the whole operation
 880                         $this->mAffectedRows = $numrowsinserted;
 881
 882                         // IGNORE always returns true
 883                         return true;
 884                 }
 885
 886                 return $res;
 887         }
 888
 889         /**
 890          * INSERT SELECT wrapper
 891          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 892          * Source items may be literals rather then field names, but strings should
 893          * be quoted with Database::addQuotes()
 894          * $conds may be "*" to copy the whole table
 895          * srcTable may be an array of tables.
 896          * @todo FIXME: Implement this a little better (seperate select/insert)?
 897          *
 898          * @param string $destTable
 899          * @param array|string $srcTable
 900          * @param array $varMap
 901          * @param array $conds
 902          * @param string $fname
 903          * @param array $insertOptions
 904          * @param array $selectOptions
 905          * @return bool
 906          */
 907         function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 908                 $insertOptions = [], $selectOptions = [] ) {
 909                 $destTable = $this->tableName( $destTable );
 910
 911                 if ( !is_array( $insertOptions ) ) {
 912                         $insertOptions = [ $insertOptions ];
 913                 }
 914
 915                 /*
 916                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 917                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 918                  */
 919                 $savepoint = null;
 920                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 921                         $savepoint = new SavepointPostgres( $this, 'mw' );
 922                         $olde = error_reporting( 0 );
 923                         $numrowsinserted = 0;
 924                         $savepoint->savepoint();
 925                 }
 926
 927                 if ( !is_array( $selectOptions ) ) {
 928                         $selectOptions = [ $selectOptions ];
 929                 }
 930                 list( $startOpts, $useIndex, $tailOpts, $ignoreIndex ) =
 931                         $this->makeSelectOptions( $selectOptions );
 932                 if ( is_array( $srcTable ) ) {
 933                         $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
 934                 } else {
 935                         $srcTable = $this->tableName( $srcTable );
 936                 }
 937
 938                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 939                         " SELECT $startOpts " . implode( ',', $varMap ) .
 940                         " FROM $srcTable $useIndex $ignoreIndex ";
 941
 942                 if ( $conds != '*' ) {
 943                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 944                 }
 945
 946                 $sql .= " $tailOpts";
 947
 948                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 949                 if ( $savepoint ) {
 950                         $bar = pg_result_error( $this->mLastResult );
 951                         if ( $bar != false ) {
 952                                 $savepoint->rollback();
 953                         } else {
 954                                 $savepoint->release();
 955                                 $numrowsinserted++;
 956                         }
 957                         error_reporting( $olde );
 958                         $savepoint->commit();
 959
 960                         // Set the affected row count for the whole operation
 961                         $this->mAffectedRows = $numrowsinserted;
 962
 963                         // IGNORE always returns true
 964                         return true;
 965                 }
 966
 967                 return $res;
 968         }
 969
 970         function tableName( $name, $format = 'quoted' ) {
 971                 # Replace reserved words with better ones
 972                 switch ( $name ) {
 973                         case 'user':
 974                                 return $this->realTableName( 'mwuser', $format );
 975                         case 'text':
 976                                 return $this->realTableName( 'pagecontent', $format );
 977                         default:
 978                                 return $this->realTableName( $name, $format );
 979                 }
 980         }
 981
 982         /* Don't cheat on installer */
 983         function realTableName( $name, $format = 'quoted' ) {
 984                 return parent::tableName( $name, $format );
 985         }
 986
 987         /**
 988          * Return the next in a sequence, save the value for retrieval via insertId()
 989          *
 990          * @param string $seqName
 991          * @return int|null
 992          */
 993         function nextSequenceValue( $seqName ) {
 994                 $safeseq = str_replace( "'", "''", $seqName );
 995                 $res = $this->query( "SELECT nextval('$safeseq')" );
 996                 $row = $this->fetchRow( $res );
 997                 $this->mInsertId = $row[0];
 998
 999                 return $this->mInsertId;
1000         }
1001
1002         /**
1003          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1004          *
1005          * @param string $seqName
1006          * @return int
1007          */
1008         function currentSequenceValue( $seqName ) {
1009                 $safeseq = str_replace( "'", "''", $seqName );
1010                 $res = $this->query( "SELECT currval('$safeseq')" );
1011                 $row = $this->fetchRow( $res );
1012                 $currval = $row[0];
1013
1014                 return $currval;
1015         }
1016
1017         # Returns the size of a text field, or -1 for "unlimited"
1018         function textFieldSize( $table, $field ) {
1019                 $table = $this->tableName( $table );
1020                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1021                         FROM pg_class c, pg_attribute a, pg_type t
1022                         WHERE relname='$table' AND a.attrelid=c.oid AND
1023                                 a.atttypid=t.oid and a.attname='$field'";
1024                 $res = $this->query( $sql );
1025                 $row = $this->fetchObject( $res );
1026                 if ( $row->ftype == 'varchar' ) {
1027                         $size = $row->size - 4;
1028                 } else {
1029                         $size = $row->size;
1030                 }
1031
1032                 return $size;
1033         }
1034
1035         function limitResult( $sql, $limit, $offset = false ) {
1036                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1037         }
1038
1039         function wasDeadlock() {
1040                 return $this->lastErrno() == '40P01';
1041         }
1042
1043         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1044                 $newName = $this->addIdentifierQuotes( $newName );
1045                 $oldName = $this->addIdentifierQuotes( $oldName );
1046
1047                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1048                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1049         }
1050
1051         function listTables( $prefix = null, $fname = __METHOD__ ) {
1052                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1053                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1054                 $endArray = [];
1055
1056                 foreach ( $result as $table ) {
1057                         $vars = get_object_vars( $table );
1058                         $table = array_pop( $vars );
1059                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1060                                 $endArray[] = $table;
1061                         }
1062                 }
1063
1064                 return $endArray;
1065         }
1066
1067         function timestamp( $ts = 0 ) {
1068                 return wfTimestamp( TS_POSTGRES, $ts );
1069         }
1070
1071         /**
1072          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1073          * to http://www.php.net/manual/en/ref.pgsql.php
1074          *
1075          * Parsing a postgres array can be a tricky problem, he's my
1076          * take on this, it handles multi-dimensional arrays plus
1077          * escaping using a nasty regexp to determine the limits of each
1078          * data-item.
1079          *
1080          * This should really be handled by PHP PostgreSQL module
1081          *
1082          * @since 1.19
1083          * @param string $text Postgreql array returned in a text form like {a,b}
1084          * @param string $output
1085          * @param int $limit
1086          * @param int $offset
1087          * @return string
1088          */
1089         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1090                 if ( false === $limit ) {
1091                         $limit = strlen( $text ) - 1;
1092                         $output = [];
1093                 }
1094                 if ( '{}' == $text ) {
1095                         return $output;
1096                 }
1097                 do {
1098                         if ( '{' != $text[$offset] ) {
1099                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1100                                         $text, $match, 0, $offset );
1101                                 $offset += strlen( $match[0] );
1102                                 $output[] = ( '"' != $match[1][0]
1103                                         ? $match[1]
1104                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1105                                 if ( '},' == $match[3] ) {
1106                                         return $output;
1107                                 }
1108                         } else {
1109                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1110                         }
1111                 } while ( $limit > $offset );
1112
1113                 return $output;
1114         }
1115
1116         /**
1117          * Return aggregated value function call
1118          * @param array $valuedata
1119          * @param string $valuename
1120          * @return array
1121          */
1122         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1123                 return $valuedata;
1124         }
1125
1126         /**
1127          * @return string Wikitext of a link to the server software's web site
1128          */
1129         public function getSoftwareLink() {
1130                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1131         }
1132
1133         /**
1134          * Return current schema (executes SELECT current_schema())
1135          * Needs transaction
1136          *
1137          * @since 1.19
1138          * @return string Default schema for the current session
1139          */
1140         function getCurrentSchema() {
1141                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1142                 $row = $this->fetchRow( $res );
1143
1144                 return $row[0];
1145         }
1146
1147         /**
1148          * Return list of schemas which are accessible without schema name
1149          * This is list does not contain magic keywords like "$user"
1150          * Needs transaction
1151          *
1152          * @see getSearchPath()
1153          * @see setSearchPath()
1154          * @since 1.19
1155          * @return array List of actual schemas for the current sesson
1156          */
1157         function getSchemas() {
1158                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1159                 $row = $this->fetchRow( $res );
1160                 $schemas = [];
1161
1162                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1163
1164                 return $this->pg_array_parse( $row[0], $schemas );
1165         }
1166
1167         /**
1168          * Return search patch for schemas
1169          * This is different from getSchemas() since it contain magic keywords
1170          * (like "$user").
1171          * Needs transaction
1172          *
1173          * @since 1.19
1174          * @return array How to search for table names schemas for the current user
1175          */
1176         function getSearchPath() {
1177                 $res = $this->query( "SHOW search_path", __METHOD__ );
1178                 $row = $this->fetchRow( $res );
1179
1180                 /* PostgreSQL returns SHOW values as strings */
1181
1182                 return explode( ",", $row[0] );
1183         }
1184
1185         /**
1186          * Update search_path, values should already be sanitized
1187          * Values may contain magic keywords like "$user"
1188          * @since 1.19
1189          *
1190          * @param array $search_path List of schemas to be searched by default
1191          */
1192         function setSearchPath( $search_path ) {
1193                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1194         }
1195
1196         /**
1197          * Determine default schema for MediaWiki core
1198          * Adjust this session schema search path if desired schema exists
1199          * and is not alread there.
1200          *
1201          * We need to have name of the core schema stored to be able
1202          * to query database metadata.
1203          *
1204          * This will be also called by the installer after the schema is created
1205          *
1206          * @since 1.19
1207          *
1208          * @param string $desiredSchema
1209          */
1210         function determineCoreSchema( $desiredSchema ) {
1211                 $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
1212                 if ( $this->schemaExists( $desiredSchema ) ) {
1213                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1214                                 $this->mCoreSchema = $desiredSchema;
1215                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1216                         } else {
1217                                 /**
1218                                  * Prepend our schema (e.g. 'mediawiki') in front
1219                                  * of the search path
1220                                  * Fixes bug 15816
1221                                  */
1222                                 $search_path = $this->getSearchPath();
1223                                 array_unshift( $search_path,
1224                                         $this->addIdentifierQuotes( $desiredSchema ) );
1225                                 $this->setSearchPath( $search_path );
1226                                 $this->mCoreSchema = $desiredSchema;
1227                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1228                         }
1229                 } else {
1230                         $this->mCoreSchema = $this->getCurrentSchema();
1231                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1232                                 $this->mCoreSchema . "\"\n" );
1233                 }
1234                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1235                 $this->commit( __METHOD__ );
1236         }
1237
1238         /**
1239          * Return schema name fore core MediaWiki tables
1240          *
1241          * @since 1.19
1242          * @return string Core schema name
1243          */
1244         function getCoreSchema() {
1245                 return $this->mCoreSchema;
1246         }
1247
1248         /**
1249          * @return string Version information from the database
1250          */
1251         function getServerVersion() {
1252                 if ( !isset( $this->numericVersion ) ) {
1253                         $versionInfo = pg_version( $this->mConn );
1254                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1255                                 // Old client, abort install
1256                                 $this->numericVersion = '7.3 or earlier';
1257                         } elseif ( isset( $versionInfo['server'] ) ) {
1258                                 // Normal client
1259                                 $this->numericVersion = $versionInfo['server'];
1260                         } else {
1261                                 // Bug 16937: broken pgsql extension from PHP<5.3
1262                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1263                         }
1264                 }
1265
1266                 return $this->numericVersion;
1267         }
1268
1269         /**
1270          * Query whether a given relation exists (in the given schema, or the
1271          * default mw one if not given)
1272          * @param string $table
1273          * @param array|string $types
1274          * @param bool|string $schema
1275          * @return bool
1276          */
1277         function relationExists( $table, $types, $schema = false ) {
1278                 if ( !is_array( $types ) ) {
1279                         $types = [ $types ];
1280                 }
1281                 if ( !$schema ) {
1282                         $schema = $this->getCoreSchema();
1283                 }
1284                 $table = $this->realTableName( $table, 'raw' );
1285                 $etable = $this->addQuotes( $table );
1286                 $eschema = $this->addQuotes( $schema );
1287                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1288                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1289                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1290                 $res = $this->query( $sql );
1291                 $count = $res ? $res->numRows() : 0;
1292
1293                 return (bool)$count;
1294         }
1295
1296         /**
1297          * For backward compatibility, this function checks both tables and
1298          * views.
1299          * @param string $table
1300          * @param string $fname
1301          * @param bool|string $schema
1302          * @return bool
1303          */
1304         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1305                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1306         }
1307
1308         function sequenceExists( $sequence, $schema = false ) {
1309                 return $this->relationExists( $sequence, 'S', $schema );
1310         }
1311
1312         function triggerExists( $table, $trigger ) {
1313                 $q = <<<SQL
1314         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1315                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1316                           AND tgrelid=pg_class.oid
1317                           AND nspname=%s AND relname=%s AND tgname=%s
1318 SQL;
1319                 $res = $this->query(
1320                         sprintf(
1321                                 $q,
1322                                 $this->addQuotes( $this->getCoreSchema() ),
1323                                 $this->addQuotes( $table ),
1324                                 $this->addQuotes( $trigger )
1325                         )
1326                 );
1327                 if ( !$res ) {
1328                         return null;
1329                 }
1330                 $rows = $res->numRows();
1331
1332                 return $rows;
1333         }
1334
1335         function ruleExists( $table, $rule ) {
1336                 $exists = $this->selectField( 'pg_rules', 'rulename',
1337                         [
1338                                 'rulename' => $rule,
1339                                 'tablename' => $table,
1340                                 'schemaname' => $this->getCoreSchema()
1341                         ]
1342                 );
1343
1344                 return $exists === $rule;
1345         }
1346
1347         function constraintExists( $table, $constraint ) {
1348                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1349                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1350                         $this->addQuotes( $this->getCoreSchema() ),
1351                         $this->addQuotes( $table ),
1352                         $this->addQuotes( $constraint )
1353                 );
1354                 $res = $this->query( $sql );
1355                 if ( !$res ) {
1356                         return null;
1357                 }
1358                 $rows = $res->numRows();
1359
1360                 return $rows;
1361         }
1362
1363         /**
1364          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1365          * @param string $schema
1366          * @return bool
1367          */
1368         function schemaExists( $schema ) {
1369                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1370                         [ 'nspname' => $schema ], __METHOD__ );
1371
1372                 return (bool)$exists;
1373         }
1374
1375         /**
1376          * Returns true if a given role (i.e. user) exists, false otherwise.
1377          * @param string $roleName
1378          * @return bool
1379          */
1380         function roleExists( $roleName ) {
1381                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1382                         [ 'rolname' => $roleName ], __METHOD__ );
1383
1384                 return (bool)$exists;
1385         }
1386
1387         /**
1388          * @var string $table
1389          * @var string $field
1390          * @return PostgresField|null
1391          */
1392         function fieldInfo( $table, $field ) {
1393                 return PostgresField::fromText( $this, $table, $field );
1394         }
1395
1396         /**
1397          * pg_field_type() wrapper
1398          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1399          * @param int $index Field number, starting from 0
1400          * @return string
1401          */
1402         function fieldType( $res, $index ) {
1403                 if ( $res instanceof ResultWrapper ) {
1404                         $res = $res->result;
1405                 }
1406
1407                 return pg_field_type( $res, $index );
1408         }
1409
1410         /**
1411          * @param string $b
1412          * @return Blob
1413          */
1414         function encodeBlob( $b ) {
1415                 return new PostgresBlob( pg_escape_bytea( $b ) );
1416         }
1417
1418         function decodeBlob( $b ) {
1419                 if ( $b instanceof PostgresBlob ) {
1420                         $b = $b->fetch();
1421                 } elseif ( $b instanceof Blob ) {
1422                         return $b->fetch();
1423                 }
1424
1425                 return pg_unescape_bytea( $b );
1426         }
1427
1428         function strencode( $s ) {
1429                 // Should not be called by us
1430
1431                 return pg_escape_string( $this->mConn, $s );
1432         }
1433
1434         /**
1435          * @param null|bool|Blob $s
1436          * @return int|string
1437          */
1438         function addQuotes( $s ) {
1439                 if ( is_null( $s ) ) {
1440                         return 'NULL';
1441                 } elseif ( is_bool( $s ) ) {
1442                         return intval( $s );
1443                 } elseif ( $s instanceof Blob ) {
1444                         if ( $s instanceof PostgresBlob ) {
1445                                 $s = $s->fetch();
1446                         } else {
1447                                 $s = pg_escape_bytea( $this->mConn, $s->fetch() );
1448                         }
1449                         return "'$s'";
1450                 }
1451
1452                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1453         }
1454
1455         /**
1456          * Postgres specific version of replaceVars.
1457          * Calls the parent version in Database.php
1458          *
1459          * @param string $ins SQL string, read from a stream (usually tables.sql)
1460          * @return string SQL string
1461          */
1462         protected function replaceVars( $ins ) {
1463                 $ins = parent::replaceVars( $ins );
1464
1465                 if ( $this->numericVersion >= 8.3 ) {
1466                         // Thanks for not providing backwards-compatibility, 8.3
1467                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1468                 }
1469
1470                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1471                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1472                 }
1473
1474                 return $ins;
1475         }
1476
1477         /**
1478          * Various select options
1479          *
1480          * @param array $options An associative array of options to be turned into
1481          *   an SQL query, valid keys are listed in the function.
1482          * @return array
1483          */
1484         function makeSelectOptions( $options ) {
1485                 $preLimitTail = $postLimitTail = '';
1486                 $startOpts = $useIndex = $ignoreIndex = '';
1487
1488                 $noKeyOptions = [];
1489                 foreach ( $options as $key => $option ) {
1490                         if ( is_numeric( $key ) ) {
1491                                 $noKeyOptions[$option] = true;
1492                         }
1493                 }
1494
1495                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1496
1497                 $preLimitTail .= $this->makeOrderBy( $options );
1498
1499                 // if ( isset( $options['LIMIT'] ) ) {
1500                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1501                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1502                 //              : false );
1503                 // }
1504
1505                 if ( isset( $options['FOR UPDATE'] ) ) {
1506                         $postLimitTail .= ' FOR UPDATE OF ' .
1507                                 implode( ', ', array_map( [ &$this, 'tableName' ], $options['FOR UPDATE'] ) );
1508                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1509                         $postLimitTail .= ' FOR UPDATE';
1510                 }
1511
1512                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1513                         $startOpts .= 'DISTINCT';
1514                 }
1515
1516                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1517         }
1518
1519         function getDBname() {
1520                 return $this->mDBname;
1521         }
1522
1523         function getServer() {
1524                 return $this->mServer;
1525         }
1526
1527         function buildConcat( $stringList ) {
1528                 return implode( ' || ', $stringList );
1529         }
1530
1531         public function buildGroupConcatField(
1532                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1533         ) {
1534                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1535
1536                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1537         }
1538
1539         /**
1540          * @param string $field Field or column to cast
1541          * @return string
1542          * @since 1.28
1543          */
1544         public function buildStringCast( $field ) {
1545                 return $field . '::text';
1546         }
1547
1548         public function getSearchEngine() {
1549                 return 'SearchPostgres';
1550         }
1551
1552         public function streamStatementEnd( &$sql, &$newLine ) {
1553                 # Allow dollar quoting for function declarations
1554                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1555                         if ( $this->delimiter ) {
1556                                 $this->delimiter = false;
1557                         } else {
1558                                 $this->delimiter = ';';
1559                         }
1560                 }
1561
1562                 return parent::streamStatementEnd( $sql, $newLine );
1563         }
1564
1565         /**
1566          * Check to see if a named lock is available. This is non-blocking.
1567          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1568          *
1569          * @param string $lockName Name of lock to poll
1570          * @param string $method Name of method calling us
1571          * @return bool
1572          * @since 1.20
1573          */
1574         public function lockIsFree( $lockName, $method ) {
1575                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1576                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1577                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1578                 $row = $this->fetchObject( $result );
1579
1580                 return ( $row->lockstatus === 't' );
1581         }
1582
1583         /**
1584          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1585          * @param string $lockName
1586          * @param string $method
1587          * @param int $timeout
1588          * @return bool
1589          */
1590         public function lock( $lockName, $method, $timeout = 5 ) {
1591                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1592                 $loop = new WaitConditionLoop(
1593                         function () use ( $lockName, $key, $timeout, $method ) {
1594                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1595                                 $row = $this->fetchObject( $res );
1596                                 if ( $row->lockstatus === 't' ) {
1597                                         parent::lock( $lockName, $method, $timeout ); // record
1598                                         return true;
1599                                 }
1600
1601                                 return WaitConditionLoop::CONDITION_CONTINUE;
1602                         },
1603                         $timeout
1604                 );
1605
1606                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1607         }
1608
1609         /**
1610          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1611          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1612          * @param string $lockName
1613          * @param string $method
1614          * @return bool
1615          */
1616         public function unlock( $lockName, $method ) {
1617                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1618                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1619                 $row = $this->fetchObject( $result );
1620
1621                 if ( $row->lockstatus === 't' ) {
1622                         parent::unlock( $lockName, $method ); // record
1623                         return true;
1624                 }
1625
1626                 wfDebug( __METHOD__ . " failed to release lock\n" );
1627
1628                 return false;
1629         }
1630
1631         /**
1632          * @param string $lockName
1633          * @return string Integer
1634          */
1635         private function bigintFromLockName( $lockName ) {
1636                 return Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1637         }
1638 } // end DatabasePostgres class
1639
1640 class PostgresBlob extends Blob {
1641 }