src/Database/Database.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Database;
  23
  24 use Friendica\Core\Config\Cache;
  25 use Friendica\Core\System;
  26 use Friendica\Network\HTTPException\InternalServerErrorException;
  27 use Friendica\Util\DateTimeFormat;
  28 use Friendica\Util\Profiler;
  29 use mysqli;
  30 use mysqli_result;
  31 use mysqli_stmt;
  32 use PDO;
  33 use PDOException;
  34 use PDOStatement;
  35 use Psr\Log\LoggerInterface;
  36
  37 /**
  38  * This class is for the low level database stuff that does driver specific things.
  39  */
  40 class Database
  41 {
  42         protected $connected = false;
  43
  44         /**
  45          * @var Cache
  46          */
  47         protected $configCache;
  48         /**
  49          * @var Profiler
  50          */
  51         protected $profiler;
  52         /**
  53          * @var LoggerInterface
  54          */
  55         protected $logger;
  56         protected $server_info    = '';
  57         /** @var PDO|mysqli */
  58         protected $connection;
  59         protected $driver;
  60         private $error          = false;
  61         private $errorno        = 0;
  62         private $affected_rows  = 0;
  63         protected $in_transaction = false;
  64         protected $in_retrial     = false;
  65         private $relation       = [];
  66
  67         public function __construct(Cache $configCache, Profiler $profiler, LoggerInterface $logger, array $server = [])
  68         {
  69                 // We are storing these values for being able to perform a reconnect
  70                 $this->configCache   = $configCache;
  71                 $this->profiler      = $profiler;
  72                 $this->logger        = $logger;
  73
  74                 $this->readServerVariables($server);
  75                 $this->connect();
  76
  77                 if ($this->isConnected()) {
  78                         // Loads DB_UPDATE_VERSION constant
  79                         DBStructure::definition($configCache->get('system', 'basepath'), false);
  80                 }
  81         }
  82
  83         private function readServerVariables(array $server)
  84         {
  85                 // Use environment variables for mysql if they are set beforehand
  86                 if (!empty($server['MYSQL_HOST'])
  87                     && (!empty($server['MYSQL_USERNAME'] || !empty($server['MYSQL_USER'])))
  88                     && $server['MYSQL_PASSWORD'] !== false
  89                     && !empty($server['MYSQL_DATABASE']))
  90                 {
  91                         $db_host = $server['MYSQL_HOST'];
  92                         if (!empty($server['MYSQL_PORT'])) {
  93                                 $db_host .= ':' . $server['MYSQL_PORT'];
  94                         }
  95                         $this->configCache->set('database', 'hostname', $db_host);
  96                         unset($db_host);
  97                         if (!empty($server['MYSQL_USERNAME'])) {
  98                                 $this->configCache->set('database', 'username', $server['MYSQL_USERNAME']);
  99                         } else {
 100                                 $this->configCache->set('database', 'username', $server['MYSQL_USER']);
 101                         }
 102                         $this->configCache->set('database', 'password', (string) $server['MYSQL_PASSWORD']);
 103                         $this->configCache->set('database', 'database', $server['MYSQL_DATABASE']);
 104                 }
 105         }
 106
 107         public function connect()
 108         {
 109                 if (!is_null($this->connection) && $this->connected()) {
 110                         return $this->connected;
 111                 }
 112
 113                 // Reset connected state
 114                 $this->connected = false;
 115
 116                 $port       = 0;
 117                 $serveraddr = trim($this->configCache->get('database', 'hostname'));
 118                 $serverdata = explode(':', $serveraddr);
 119                 $server     = $serverdata[0];
 120                 if (count($serverdata) > 1) {
 121                         $port = trim($serverdata[1]);
 122                 }
 123                 $server  = trim($server);
 124                 $user    = trim($this->configCache->get('database', 'username'));
 125                 $pass    = trim($this->configCache->get('database', 'password'));
 126                 $db      = trim($this->configCache->get('database', 'database'));
 127                 $charset = trim($this->configCache->get('database', 'charset'));
 128
 129                 if (!(strlen($server) && strlen($user))) {
 130                         return false;
 131                 }
 132
 133                 if (class_exists('\PDO') && in_array('mysql', PDO::getAvailableDrivers())) {
 134                         $this->driver = 'pdo';
 135                         $connect      = "mysql:host=" . $server . ";dbname=" . $db;
 136
 137                         if ($port > 0) {
 138                                 $connect .= ";port=" . $port;
 139                         }
 140
 141                         if ($charset) {
 142                                 $connect .= ";charset=" . $charset;
 143                         }
 144
 145                         try {
 146                                 $this->connection = @new PDO($connect, $user, $pass);
 147                                 $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
 148                                 $this->connected = true;
 149                         } catch (PDOException $e) {
 150                                 $this->connected = false;
 151                         }
 152                 }
 153
 154                 if (!$this->connected && class_exists('\mysqli')) {
 155                         $this->driver = 'mysqli';
 156
 157                         if ($port > 0) {
 158                                 $this->connection = @new mysqli($server, $user, $pass, $db, $port);
 159                         } else {
 160                                 $this->connection = @new mysqli($server, $user, $pass, $db);
 161                         }
 162
 163                         if (!mysqli_connect_errno()) {
 164                                 $this->connected = true;
 165
 166                                 if ($charset) {
 167                                         $this->connection->set_charset($charset);
 168                                 }
 169                         }
 170                 }
 171
 172                 // No suitable SQL driver was found.
 173                 if (!$this->connected) {
 174                         $this->driver     = null;
 175                         $this->connection = null;
 176                 }
 177
 178                 return $this->connected;
 179         }
 180
 181         /**
 182          * Sets the logger for DBA
 183          *
 184          * @note this is necessary because if we want to load the logger configuration
 185          *       from the DB, but there's an error, we would print out an exception.
 186          *       So the logger gets updated after the logger configuration can be retrieved
 187          *       from the database
 188          *
 189          * @param LoggerInterface $logger
 190          */
 191         public function setLogger(LoggerInterface $logger)
 192         {
 193                 $this->logger = $logger;
 194         }
 195
 196         /**
 197          * Sets the profiler for DBA
 198          *
 199          * @param Profiler $profiler
 200          */
 201         public function setProfiler(Profiler $profiler)
 202         {
 203                 $this->profiler = $profiler;
 204         }
 205         /**
 206          * Disconnects the current database connection
 207          */
 208         public function disconnect()
 209         {
 210                 if (!is_null($this->connection)) {
 211                         switch ($this->driver) {
 212                                 case 'pdo':
 213                                         $this->connection = null;
 214                                         break;
 215                                 case 'mysqli':
 216                                         $this->connection->close();
 217                                         $this->connection = null;
 218                                         break;
 219                         }
 220                 }
 221
 222                 $this->driver    = null;
 223                 $this->connected = false;
 224         }
 225
 226         /**
 227          * Perform a reconnect of an existing database connection
 228          */
 229         public function reconnect()
 230         {
 231                 $this->disconnect();
 232                 return $this->connect();
 233         }
 234
 235         /**
 236          * Return the database object.
 237          *
 238          * @return PDO|mysqli
 239          */
 240         public function getConnection()
 241         {
 242                 return $this->connection;
 243         }
 244
 245         /**
 246          * Returns the MySQL server version string
 247          *
 248          * This function discriminate between the deprecated mysql API and the current
 249          * object-oriented mysqli API. Example of returned string: 5.5.46-0+deb8u1
 250          *
 251          * @return string
 252          */
 253         public function serverInfo()
 254         {
 255                 if ($this->server_info == '') {
 256                         switch ($this->driver) {
 257                                 case 'pdo':
 258                                         $this->server_info = $this->connection->getAttribute(PDO::ATTR_SERVER_VERSION);
 259                                         break;
 260                                 case 'mysqli':
 261                                         $this->server_info = $this->connection->server_info;
 262                                         break;
 263                         }
 264                 }
 265                 return $this->server_info;
 266         }
 267
 268         /**
 269          * Returns the selected database name
 270          *
 271          * @return string
 272          * @throws \Exception
 273          */
 274         public function databaseName()
 275         {
 276                 $ret  = $this->p("SELECT DATABASE() AS `db`");
 277                 $data = $this->toArray($ret);
 278                 return $data[0]['db'];
 279         }
 280
 281         /**
 282          * Analyze a database query and log this if some conditions are met.
 283          *
 284          * @param string $query The database query that will be analyzed
 285          *
 286          * @throws \Exception
 287          */
 288         private function logIndex($query)
 289         {
 290
 291                 if (!$this->configCache->get('system', 'db_log_index')) {
 292                         return;
 293                 }
 294
 295                 // Don't explain an explain statement
 296                 if (strtolower(substr($query, 0, 7)) == "explain") {
 297                         return;
 298                 }
 299
 300                 // Only do the explain on "select", "update" and "delete"
 301                 if (!in_array(strtolower(substr($query, 0, 6)), ["select", "update", "delete"])) {
 302                         return;
 303                 }
 304
 305                 $r = $this->p("EXPLAIN " . $query);
 306                 if (!$this->isResult($r)) {
 307                         return;
 308                 }
 309
 310                 $watchlist = explode(',', $this->configCache->get('system', 'db_log_index_watch'));
 311                 $blacklist = explode(',', $this->configCache->get('system', 'db_log_index_blacklist'));
 312
 313                 while ($row = $this->fetch($r)) {
 314                         if ((intval($this->configCache->get('system', 'db_loglimit_index')) > 0)) {
 315                                 $log = (in_array($row['key'], $watchlist) &&
 316                                         ($row['rows'] >= intval($this->configCache->get('system', 'db_loglimit_index'))));
 317                         } else {
 318                                 $log = false;
 319                         }
 320
 321                         if ((intval($this->configCache->get('system', 'db_loglimit_index_high')) > 0) && ($row['rows'] >= intval($this->configCache->get('system', 'db_loglimit_index_high')))) {
 322                                 $log = true;
 323                         }
 324
 325                         if (in_array($row['key'], $blacklist) || ($row['key'] == "")) {
 326                                 $log = false;
 327                         }
 328
 329                         if ($log) {
 330                                 $backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
 331                                 @file_put_contents($this->configCache->get('system', 'db_log_index'), DateTimeFormat::utcNow() . "\t" .
 332                                                                                                       $row['key'] . "\t" . $row['rows'] . "\t" . $row['Extra'] . "\t" .
 333                                                                                                       basename($backtrace[1]["file"]) . "\t" .
 334                                                                                                       $backtrace[1]["line"] . "\t" . $backtrace[2]["function"] . "\t" .
 335                                                                                                       substr($query, 0, 2000) . "\n", FILE_APPEND);
 336                         }
 337                 }
 338         }
 339
 340         /**
 341          * Removes every not whitelisted character from the identifier string
 342          *
 343          * @param string $identifier
 344          *
 345          * @return string sanitized identifier
 346          * @throws \Exception
 347          */
 348         private function sanitizeIdentifier($identifier)
 349         {
 350                 return preg_replace('/[^A-Za-z0-9_\-]+/', '', $identifier);
 351         }
 352
 353         public function escape($str)
 354         {
 355                 if ($this->connected) {
 356                         switch ($this->driver) {
 357                                 case 'pdo':
 358                                         return substr(@$this->connection->quote($str, PDO::PARAM_STR), 1, -1);
 359
 360                                 case 'mysqli':
 361                                         return @$this->connection->real_escape_string($str);
 362                         }
 363                 } else {
 364                         return str_replace("'", "\\'", $str);
 365                 }
 366         }
 367
 368         public function isConnected()
 369         {
 370                 return $this->connected;
 371         }
 372
 373         public function connected()
 374         {
 375                 $connected = false;
 376
 377                 if (is_null($this->connection)) {
 378                         return false;
 379                 }
 380
 381                 switch ($this->driver) {
 382                         case 'pdo':
 383                                 $r = $this->p("SELECT 1");
 384                                 if ($this->isResult($r)) {
 385                                         $row       = $this->toArray($r);
 386                                         $connected = ($row[0]['1'] == '1');
 387                                 }
 388                                 break;
 389                         case 'mysqli':
 390                                 $connected = $this->connection->ping();
 391                                 break;
 392                 }
 393
 394                 return $connected;
 395         }
 396
 397         /**
 398          * Replaces ANY_VALUE() function by MIN() function,
 399          * if the database server does not support ANY_VALUE().
 400          *
 401          * Considerations for Standard SQL, or MySQL with ONLY_FULL_GROUP_BY (default since 5.7.5).
 402          * ANY_VALUE() is available from MySQL 5.7.5 https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html
 403          * A standard fall-back is to use MIN().
 404          *
 405          * @param string $sql An SQL string without the values
 406          *
 407          * @return string The input SQL string modified if necessary.
 408          */
 409         public function anyValueFallback($sql)
 410         {
 411                 $server_info = $this->serverInfo();
 412                 if (version_compare($server_info, '5.7.5', '<') ||
 413                     (stripos($server_info, 'MariaDB') !== false)) {
 414                         $sql = str_ireplace('ANY_VALUE(', 'MIN(', $sql);
 415                 }
 416                 return $sql;
 417         }
 418
 419         /**
 420          * Replaces the ? placeholders with the parameters in the $args array
 421          *
 422          * @param string $sql  SQL query
 423          * @param array  $args The parameters that are to replace the ? placeholders
 424          *
 425          * @return string The replaced SQL query
 426          */
 427         private function replaceParameters($sql, $args)
 428         {
 429                 $offset = 0;
 430                 foreach ($args AS $param => $value) {
 431                         if (is_int($args[$param]) || is_float($args[$param])) {
 432                                 $replace = intval($args[$param]);
 433                         } else {
 434                                 $replace = "'" . $this->escape($args[$param]) . "'";
 435                         }
 436
 437                         $pos = strpos($sql, '?', $offset);
 438                         if ($pos !== false) {
 439                                 $sql = substr_replace($sql, $replace, $pos, 1);
 440                         }
 441                         $offset = $pos + strlen($replace);
 442                 }
 443                 return $sql;
 444         }
 445
 446         /**
 447          * Executes a prepared statement that returns data
 448          *
 449          * @usage Example: $r = p("SELECT * FROM `item` WHERE `guid` = ?", $guid);
 450          *
 451          * Please only use it with complicated queries.
 452          * For all regular queries please use DBA::select or DBA::exists
 453          *
 454          * @param string $sql SQL statement
 455          *
 456          * @return bool|object statement object or result object
 457          * @throws \Exception
 458          */
 459         public function p($sql)
 460         {
 461
 462                 $stamp1 = microtime(true);
 463
 464                 $params = DBA::getParam(func_get_args());
 465
 466                 // Renumber the array keys to be sure that they fit
 467                 $i    = 0;
 468                 $args = [];
 469                 foreach ($params AS $param) {
 470                         // Avoid problems with some MySQL servers and boolean values. See issue #3645
 471                         if (is_bool($param)) {
 472                                 $param = (int)$param;
 473                         }
 474                         $args[++$i] = $param;
 475                 }
 476
 477                 if (!$this->connected) {
 478                         return false;
 479                 }
 480
 481                 if ((substr_count($sql, '?') != count($args)) && (count($args) > 0)) {
 482                         // Question: Should we continue or stop the query here?
 483                         $this->logger->warning('Query parameters mismatch.', ['query' => $sql, 'args' => $args, 'callstack' => System::callstack()]);
 484                 }
 485
 486                 $sql = DBA::cleanQuery($sql);
 487                 $sql = $this->anyValueFallback($sql);
 488
 489                 $orig_sql = $sql;
 490
 491                 if ($this->configCache->get('system', 'db_callstack') !== null) {
 492                         $sql = "/*" . System::callstack() . " */ " . $sql;
 493                 }
 494
 495                 $this->error         = '';
 496                 $this->errorno       = 0;
 497                 $this->affected_rows = 0;
 498
 499                 // We have to make some things different if this function is called from "e"
 500                 $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
 501
 502                 if (isset($trace[1])) {
 503                         $called_from = $trace[1];
 504                 } else {
 505                         // We use just something that is defined to avoid warnings
 506                         $called_from = $trace[0];
 507                 }
 508                 // We are having an own error logging in the function "e"
 509                 $called_from_e = ($called_from['function'] == 'e');
 510
 511                 if (!isset($this->connection)) {
 512                         throw new InternalServerErrorException('The Connection is empty, although connected is set true.');
 513                 }
 514
 515                 switch ($this->driver) {
 516                         case 'pdo':
 517                                 // If there are no arguments we use "query"
 518                                 if (count($args) == 0) {
 519                                         if (!$retval = $this->connection->query($sql)) {
 520                                                 $errorInfo     = $this->connection->errorInfo();
 521                                                 $this->error   = $errorInfo[2];
 522                                                 $this->errorno = $errorInfo[1];
 523                                                 $retval        = false;
 524                                                 break;
 525                                         }
 526                                         $this->affected_rows = $retval->rowCount();
 527                                         break;
 528                                 }
 529
 530                                 /** @var $stmt mysqli_stmt|PDOStatement */
 531                                 if (!$stmt = $this->connection->prepare($sql)) {
 532                                         $errorInfo     = $this->connection->errorInfo();
 533                                         $this->error   = $errorInfo[2];
 534                                         $this->errorno = $errorInfo[1];
 535                                         $retval        = false;
 536                                         break;
 537                                 }
 538
 539                                 foreach ($args AS $param => $value) {
 540                                         if (is_int($args[$param])) {
 541                                                 $data_type = PDO::PARAM_INT;
 542                                         } else {
 543                                                 $data_type = PDO::PARAM_STR;
 544                                         }
 545                                         $stmt->bindParam($param, $args[$param], $data_type);
 546                                 }
 547
 548                                 if (!$stmt->execute()) {
 549                                         $errorInfo     = $stmt->errorInfo();
 550                                         $this->error   = $errorInfo[2];
 551                                         $this->errorno = $errorInfo[1];
 552                                         $retval        = false;
 553                                 } else {
 554                                         $retval              = $stmt;
 555                                         $this->affected_rows = $retval->rowCount();
 556                                 }
 557                                 break;
 558                         case 'mysqli':
 559                                 // There are SQL statements that cannot be executed with a prepared statement
 560                                 $parts           = explode(' ', $orig_sql);
 561                                 $command         = strtolower($parts[0]);
 562                                 $can_be_prepared = in_array($command, ['select', 'update', 'insert', 'delete']);
 563
 564                                 // The fallback routine is called as well when there are no arguments
 565                                 if (!$can_be_prepared || (count($args) == 0)) {
 566                                         $retval = $this->connection->query($this->replaceParameters($sql, $args));
 567                                         if ($this->connection->errno) {
 568                                                 $this->error   = $this->connection->error;
 569                                                 $this->errorno = $this->connection->errno;
 570                                                 $retval        = false;
 571                                         } else {
 572                                                 if (isset($retval->num_rows)) {
 573                                                         $this->affected_rows = $retval->num_rows;
 574                                                 } else {
 575                                                         $this->affected_rows = $this->connection->affected_rows;
 576                                                 }
 577                                         }
 578                                         break;
 579                                 }
 580
 581                                 $stmt = $this->connection->stmt_init();
 582
 583                                 if (!$stmt->prepare($sql)) {
 584                                         $this->error   = $stmt->error;
 585                                         $this->errorno = $stmt->errno;
 586                                         $retval        = false;
 587                                         break;
 588                                 }
 589
 590                                 $param_types = '';
 591                                 $values      = [];
 592                                 foreach ($args AS $param => $value) {
 593                                         if (is_int($args[$param])) {
 594                                                 $param_types .= 'i';
 595                                         } elseif (is_float($args[$param])) {
 596                                                 $param_types .= 'd';
 597                                         } elseif (is_string($args[$param])) {
 598                                                 $param_types .= 's';
 599                                         } else {
 600                                                 $param_types .= 'b';
 601                                         }
 602                                         $values[] = &$args[$param];
 603                                 }
 604
 605                                 if (count($values) > 0) {
 606                                         array_unshift($values, $param_types);
 607                                         call_user_func_array([$stmt, 'bind_param'], $values);
 608                                 }
 609
 610                                 if (!$stmt->execute()) {
 611                                         $this->error   = $this->connection->error;
 612                                         $this->errorno = $this->connection->errno;
 613                                         $retval        = false;
 614                                 } else {
 615                                         $stmt->store_result();
 616                                         $retval              = $stmt;
 617                                         $this->affected_rows = $retval->affected_rows;
 618                                 }
 619                                 break;
 620                 }
 621
 622                 // We are having an own error logging in the function "e"
 623                 if (($this->errorno != 0) && !$called_from_e) {
 624                         // We have to preserve the error code, somewhere in the logging it get lost
 625                         $error   = $this->error;
 626                         $errorno = $this->errorno;
 627
 628                         $this->logger->error('DB Error', [
 629                                 'code'      => $this->errorno,
 630                                 'error'     => $this->error,
 631                                 'callstack' => System::callstack(8),
 632                                 'params'    => $this->replaceParameters($sql, $args),
 633                         ]);
 634
 635                         // On a lost connection we try to reconnect - but only once.
 636                         if ($errorno == 2006) {
 637                                 if ($this->in_retrial || !$this->reconnect()) {
 638                                         // It doesn't make sense to continue when the database connection was lost
 639                                         if ($this->in_retrial) {
 640                                                 $this->logger->notice('Giving up retrial because of database error', [
 641                                                         'code'  => $this->errorno,
 642                                                         'error' => $this->error,
 643                                                 ]);
 644                                         } else {
 645                                                 $this->logger->notice('Couldn\'t reconnect after database error', [
 646                                                         'code'  => $this->errorno,
 647                                                         'error' => $this->error,
 648                                                 ]);
 649                                         }
 650                                         exit(1);
 651                                 } else {
 652                                         // We try it again
 653                                         $this->logger->notice('Reconnected after database error', [
 654                                                 'code'  => $this->errorno,
 655                                                 'error' => $this->error,
 656                                         ]);
 657                                         $this->in_retrial = true;
 658                                         $ret              = $this->p($sql, $args);
 659                                         $this->in_retrial = false;
 660                                         return $ret;
 661                                 }
 662                         }
 663
 664                         $this->error   = $error;
 665                         $this->errorno = $errorno;
 666                 }
 667
 668                 $this->profiler->saveTimestamp($stamp1, 'database', System::callstack());
 669
 670                 if ($this->configCache->get('system', 'db_log')) {
 671                         $stamp2   = microtime(true);
 672                         $duration = (float)($stamp2 - $stamp1);
 673
 674                         if (($duration > $this->configCache->get('system', 'db_loglimit'))) {
 675                                 $duration  = round($duration, 3);
 676                                 $backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
 677
 678                                 @file_put_contents($this->configCache->get('system', 'db_log'), DateTimeFormat::utcNow() . "\t" . $duration . "\t" .
 679                                                                                                 basename($backtrace[1]["file"]) . "\t" .
 680                                                                                                 $backtrace[1]["line"] . "\t" . $backtrace[2]["function"] . "\t" .
 681                                                                                                 substr($this->replaceParameters($sql, $args), 0, 2000) . "\n", FILE_APPEND);
 682                         }
 683                 }
 684                 return $retval;
 685         }
 686
 687         /**
 688          * Executes a prepared statement like UPDATE or INSERT that doesn't return data
 689          *
 690          * Please use DBA::delete, DBA::insert, DBA::update, ... instead
 691          *
 692          * @param string $sql SQL statement
 693          *
 694          * @return boolean Was the query successfull? False is returned only if an error occurred
 695          * @throws \Exception
 696          */
 697         public function e($sql)
 698         {
 699
 700                 $stamp = microtime(true);
 701
 702                 $params = DBA::getParam(func_get_args());
 703
 704                 // In a case of a deadlock we are repeating the query 20 times
 705                 $timeout = 20;
 706
 707                 do {
 708                         $stmt = $this->p($sql, $params);
 709
 710                         if (is_bool($stmt)) {
 711                                 $retval = $stmt;
 712                         } elseif (is_object($stmt)) {
 713                                 $retval = true;
 714                         } else {
 715                                 $retval = false;
 716                         }
 717
 718                         $this->close($stmt);
 719
 720                 } while (($this->errorno == 1213) && (--$timeout > 0));
 721
 722                 if ($this->errorno != 0) {
 723                         // We have to preserve the error code, somewhere in the logging it get lost
 724                         $error   = $this->error;
 725                         $errorno = $this->errorno;
 726
 727                         $this->logger->error('DB Error', [
 728                                 'code'      => $this->errorno,
 729                                 'error'     => $this->error,
 730                                 'callstack' => System::callstack(8),
 731                                 'params'    => $this->replaceParameters($sql, $params),
 732                         ]);
 733
 734                         // On a lost connection we simply quit.
 735                         // A reconnect like in $this->p could be dangerous with modifications
 736                         if ($errorno == 2006) {
 737                                 $this->logger->notice('Giving up because of database error', [
 738                                         'code'  => $this->errorno,
 739                                         'error' => $this->error,
 740                                 ]);
 741                                 exit(1);
 742                         }
 743
 744                         $this->error   = $error;
 745                         $this->errorno = $errorno;
 746                 }
 747
 748                 $this->profiler->saveTimestamp($stamp, "database_write", System::callstack());
 749
 750                 return $retval;
 751         }
 752
 753         /**
 754          * Check if data exists
 755          *
 756          * @param string|array $table     Table name or array [schema => table]
 757          * @param array        $condition array of fields for condition
 758          *
 759          * @return boolean Are there rows for that condition?
 760          * @throws \Exception
 761          */
 762         public function exists($table, $condition)
 763         {
 764                 if (empty($table)) {
 765                         return false;
 766                 }
 767
 768                 $fields = [];
 769
 770                 if (empty($condition)) {
 771                         return DBStructure::existsTable($table);
 772                 }
 773
 774                 reset($condition);
 775                 $first_key = key($condition);
 776                 if (!is_int($first_key)) {
 777                         $fields = [$first_key];
 778                 }
 779
 780                 $stmt = $this->select($table, $fields, $condition, ['limit' => 1]);
 781
 782                 if (is_bool($stmt)) {
 783                         $retval = $stmt;
 784                 } else {
 785                         $retval = ($this->numRows($stmt) > 0);
 786                 }
 787
 788                 $this->close($stmt);
 789
 790                 return $retval;
 791         }
 792
 793         /**
 794          * Fetches the first row
 795          *
 796          * Please use DBA::selectFirst or DBA::exists whenever this is possible.
 797          *
 798          * Fetches the first row
 799          *
 800          * @param string $sql SQL statement
 801          *
 802          * @return array first row of query
 803          * @throws \Exception
 804          */
 805         public function fetchFirst($sql)
 806         {
 807                 $params = DBA::getParam(func_get_args());
 808
 809                 $stmt = $this->p($sql, $params);
 810
 811                 if (is_bool($stmt)) {
 812                         $retval = $stmt;
 813                 } else {
 814                         $retval = $this->fetch($stmt);
 815                 }
 816
 817                 $this->close($stmt);
 818
 819                 return $retval;
 820         }
 821
 822         /**
 823          * Returns the number of affected rows of the last statement
 824          *
 825          * @return int Number of rows
 826          */
 827         public function affectedRows()
 828         {
 829                 return $this->affected_rows;
 830         }
 831
 832         /**
 833          * Returns the number of columns of a statement
 834          *
 835          * @param object Statement object
 836          *
 837          * @return int Number of columns
 838          */
 839         public function columnCount($stmt)
 840         {
 841                 if (!is_object($stmt)) {
 842                         return 0;
 843                 }
 844                 switch ($this->driver) {
 845                         case 'pdo':
 846                                 return $stmt->columnCount();
 847                         case 'mysqli':
 848                                 return $stmt->field_count;
 849                 }
 850                 return 0;
 851         }
 852
 853         /**
 854          * Returns the number of rows of a statement
 855          *
 856          * @param PDOStatement|mysqli_result|mysqli_stmt Statement object
 857          *
 858          * @return int Number of rows
 859          */
 860         public function numRows($stmt)
 861         {
 862                 if (!is_object($stmt)) {
 863                         return 0;
 864                 }
 865                 switch ($this->driver) {
 866                         case 'pdo':
 867                                 return $stmt->rowCount();
 868                         case 'mysqli':
 869                                 return $stmt->num_rows;
 870                 }
 871                 return 0;
 872         }
 873
 874         /**
 875          * Fetch a single row
 876          *
 877          * @param mixed $stmt statement object
 878          *
 879          * @return array current row
 880          */
 881         public function fetch($stmt)
 882         {
 883
 884                 $stamp1 = microtime(true);
 885
 886                 $columns = [];
 887
 888                 if (!is_object($stmt)) {
 889                         return false;
 890                 }
 891
 892                 switch ($this->driver) {
 893                         case 'pdo':
 894                                 $columns = $stmt->fetch(PDO::FETCH_ASSOC);
 895                                 break;
 896                         case 'mysqli':
 897                                 if (get_class($stmt) == 'mysqli_result') {
 898                                         $columns = $stmt->fetch_assoc();
 899                                         break;
 900                                 }
 901
 902                                 // This code works, but is slow
 903
 904                                 // Bind the result to a result array
 905                                 $cols = [];
 906
 907                                 $cols_num = [];
 908                                 for ($x = 0; $x < $stmt->field_count; $x++) {
 909                                         $cols[] = &$cols_num[$x];
 910                                 }
 911
 912                                 call_user_func_array([$stmt, 'bind_result'], $cols);
 913
 914                                 if (!$stmt->fetch()) {
 915                                         return false;
 916                                 }
 917
 918                                 // The slow part:
 919                                 // We need to get the field names for the array keys
 920                                 // It seems that there is no better way to do this.
 921                                 $result = $stmt->result_metadata();
 922                                 $fields = $result->fetch_fields();
 923
 924                                 foreach ($cols_num AS $param => $col) {
 925                                         $columns[$fields[$param]->name] = $col;
 926                                 }
 927                 }
 928
 929                 $this->profiler->saveTimestamp($stamp1, 'database', System::callstack());
 930
 931                 return $columns;
 932         }
 933
 934         /**
 935          * Insert a row into a table
 936          *
 937          * @param string|array $table               Table name or array [schema => table]
 938          * @param array        $param               parameter array
 939          * @param bool         $on_duplicate_update Do an update on a duplicate entry
 940          *
 941          * @return boolean was the insert successful?
 942          * @throws \Exception
 943          */
 944         public function insert($table, $param, $on_duplicate_update = false)
 945         {
 946                 if (empty($table) || empty($param)) {
 947                         $this->logger->info('Table and fields have to be set');
 948                         return false;
 949                 }
 950
 951                 $table_string = DBA::buildTableString($table);
 952
 953                 $fields_string = implode(', ', array_map([DBA::class, 'quoteIdentifier'], array_keys($param)));
 954
 955                 $values_string = substr(str_repeat("?, ", count($param)), 0, -2);
 956
 957                 $sql = "INSERT INTO " . $table_string . " (" . $fields_string . ") VALUES (" . $values_string . ")";
 958
 959                 if ($on_duplicate_update) {
 960                         $fields_string = implode(' = ?, ', array_map([DBA::class, 'quoteIdentifier'], array_keys($param)));
 961
 962                         $sql .= " ON DUPLICATE KEY UPDATE " . $fields_string . " = ?";
 963
 964                         $values = array_values($param);
 965                         $param  = array_merge_recursive($values, $values);
 966                 }
 967
 968                 return $this->e($sql, $param);
 969         }
 970
 971         /**
 972          * Fetch the id of the last insert command
 973          *
 974          * @return integer Last inserted id
 975          */
 976         public function lastInsertId()
 977         {
 978                 switch ($this->driver) {
 979                         case 'pdo':
 980                                 $id = $this->connection->lastInsertId();
 981                                 break;
 982                         case 'mysqli':
 983                                 $id = $this->connection->insert_id;
 984                                 break;
 985                 }
 986                 return $id;
 987         }
 988
 989         /**
 990          * Locks a table for exclusive write access
 991          *
 992          * This function can be extended in the future to accept a table array as well.
 993          *
 994          * @param string|array $table Table name or array [schema => table]
 995          *
 996          * @return boolean was the lock successful?
 997          * @throws \Exception
 998          */
 999         public function lock($table)
1000         {
1001                 // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
1002                 if ($this->driver == 'pdo') {
1003                         $this->e("SET autocommit=0");
1004                         $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
1005                 } else {
1006                         $this->connection->autocommit(false);
1007                 }
1008
1009                 $success = $this->e("LOCK TABLES " . DBA::buildTableString($table) . " WRITE");
1010
1011                 if ($this->driver == 'pdo') {
1012                         $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
1013                 }
1014
1015                 if (!$success) {
1016                         if ($this->driver == 'pdo') {
1017                                 $this->e("SET autocommit=1");
1018                         } else {
1019                                 $this->connection->autocommit(true);
1020                         }
1021                 } else {
1022                         $this->in_transaction = true;
1023                 }
1024                 return $success;
1025         }
1026
1027         /**
1028          * Unlocks all locked tables
1029          *
1030          * @return boolean was the unlock successful?
1031          * @throws \Exception
1032          */
1033         public function unlock()
1034         {
1035                 // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
1036                 $this->performCommit();
1037
1038                 if ($this->driver == 'pdo') {
1039                         $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
1040                 }
1041
1042                 $success = $this->e("UNLOCK TABLES");
1043
1044                 if ($this->driver == 'pdo') {
1045                         $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
1046                         $this->e("SET autocommit=1");
1047                 } else {
1048                         $this->connection->autocommit(true);
1049                 }
1050
1051                 $this->in_transaction = false;
1052                 return $success;
1053         }
1054
1055         /**
1056          * Starts a transaction
1057          *
1058          * @return boolean Was the command executed successfully?
1059          */
1060         public function transaction()
1061         {
1062                 if (!$this->performCommit()) {
1063                         return false;
1064                 }
1065
1066                 switch ($this->driver) {
1067                         case 'pdo':
1068                                 if (!$this->connection->inTransaction() && !$this->connection->beginTransaction()) {
1069                                         return false;
1070                                 }
1071                                 break;
1072
1073                         case 'mysqli':
1074                                 if (!$this->connection->begin_transaction()) {
1075                                         return false;
1076                                 }
1077                                 break;
1078                 }
1079
1080                 $this->in_transaction = true;
1081                 return true;
1082         }
1083
1084         protected function performCommit()
1085         {
1086                 switch ($this->driver) {
1087                         case 'pdo':
1088                                 if (!$this->connection->inTransaction()) {
1089                                         return true;
1090                                 }
1091
1092                                 return $this->connection->commit();
1093
1094                         case 'mysqli':
1095                                 return $this->connection->commit();
1096                 }
1097
1098                 return true;
1099         }
1100
1101         /**
1102          * Does a commit
1103          *
1104          * @return boolean Was the command executed successfully?
1105          */
1106         public function commit()
1107         {
1108                 if (!$this->performCommit()) {
1109                         return false;
1110                 }
1111                 $this->in_transaction = false;
1112                 return true;
1113         }
1114
1115         /**
1116          * Does a rollback
1117          *
1118          * @return boolean Was the command executed successfully?
1119          */
1120         public function rollback()
1121         {
1122                 $ret = false;
1123
1124                 switch ($this->driver) {
1125                         case 'pdo':
1126                                 if (!$this->connection->inTransaction()) {
1127                                         $ret = true;
1128                                         break;
1129                                 }
1130                                 $ret = $this->connection->rollBack();
1131                                 break;
1132
1133                         case 'mysqli':
1134                                 $ret = $this->connection->rollback();
1135                                 break;
1136                 }
1137                 $this->in_transaction = false;
1138                 return $ret;
1139         }
1140
1141         /**
1142          * Build the array with the table relations
1143          *
1144          * The array is build from the database definitions in DBStructure.php
1145          *
1146          * This process must only be started once, since the value is cached.
1147          */
1148         private function buildRelationData()
1149         {
1150                 $definition = DBStructure::definition($this->configCache->get('system', 'basepath'));
1151
1152                 foreach ($definition AS $table => $structure) {
1153                         foreach ($structure['fields'] AS $field => $field_struct) {
1154                                 if (isset($field_struct['relation'])) {
1155                                         foreach ($field_struct['relation'] AS $rel_table => $rel_field) {
1156                                                 $this->relation[$rel_table][$rel_field][$table][] = $field;
1157                                         }
1158                                 }
1159                         }
1160                 }
1161         }
1162
1163         /**
1164          * Delete a row from a table
1165          *
1166          * Note: this methods does NOT accept schema => table arrays because of the complex relation stuff.
1167          *
1168          * @param string $table      Table name
1169          * @param array  $conditions Field condition(s)
1170          * @param array  $options
1171          *                           - cascade: If true we delete records in other tables that depend on the one we're deleting through
1172          *                           relations (default: true)
1173          * @param array  $callstack  Internal use: prevent endless loops
1174          *
1175          * @return boolean was the delete successful?
1176          * @throws \Exception
1177          */
1178         public function delete($table, array $conditions, array $options = [], array &$callstack = [])
1179         {
1180                 if (empty($table) || empty($conditions)) {
1181                         $this->logger->info('Table and conditions have to be set');
1182                         return false;
1183                 }
1184
1185                 $commands = [];
1186
1187                 // Create a key for the loop prevention
1188                 $key = $table . ':' . json_encode($conditions);
1189
1190                 // We quit when this key already exists in the callstack.
1191                 if (isset($callstack[$key])) {
1192                         return true;
1193                 }
1194
1195                 $callstack[$key] = true;
1196
1197                 $commands[$key] = ['table' => $table, 'conditions' => $conditions];
1198
1199                 // Don't use "defaults" here, since it would set "false" to "true"
1200                 if (isset($options['cascade'])) {
1201                         $cascade = $options['cascade'];
1202                 } else {
1203                         $cascade = true;
1204                 }
1205
1206                 // To speed up the whole process we cache the table relations
1207                 if ($cascade && count($this->relation) == 0) {
1208                         $this->buildRelationData();
1209                 }
1210
1211                 // Is there a relation entry for the table?
1212                 if ($cascade && isset($this->relation[$table])) {
1213                         // We only allow a simple "one field" relation.
1214                         $field   = array_keys($this->relation[$table])[0];
1215                         $rel_def = array_values($this->relation[$table])[0];
1216
1217                         // Create a key for preventing double queries
1218                         $qkey = $field . '-' . $table . ':' . json_encode($conditions);
1219
1220                         // When the search field is the relation field, we don't need to fetch the rows
1221                         // This is useful when the leading record is already deleted in the frontend but the rest is done in the backend
1222                         if ((count($conditions) == 1) && ($field == array_keys($conditions)[0])) {
1223                                 foreach ($rel_def AS $rel_table => $rel_fields) {
1224                                         foreach ($rel_fields AS $rel_field) {
1225                                                 $this->delete($rel_table, [$rel_field => array_values($conditions)[0]], $options, $callstack);
1226                                         }
1227                                 }
1228                                 // We quit when this key already exists in the callstack.
1229                         } elseif (!isset($callstack[$qkey])) {
1230                                 $callstack[$qkey] = true;
1231
1232                                 // Fetch all rows that are to be deleted
1233                                 $data = $this->select($table, [$field], $conditions);
1234
1235                                 while ($row = $this->fetch($data)) {
1236                                         $this->delete($table, [$field => $row[$field]], $options, $callstack);
1237                                 }
1238
1239                                 $this->close($data);
1240
1241                                 // Since we had split the delete command we don't need the original command anymore
1242                                 unset($commands[$key]);
1243                         }
1244                 }
1245
1246                 // Now we finalize the process
1247                 $do_transaction = !$this->in_transaction;
1248
1249                 if ($do_transaction) {
1250                         $this->transaction();
1251                 }
1252
1253                 $compacted = [];
1254                 $counter   = [];
1255
1256                 foreach ($commands AS $command) {
1257                         $conditions = $command['conditions'];
1258                         reset($conditions);
1259                         $first_key = key($conditions);
1260
1261                         $condition_string = DBA::buildCondition($conditions);
1262
1263                         if ((count($command['conditions']) > 1) || is_int($first_key)) {
1264                                 $sql = "DELETE FROM " . DBA::quoteIdentifier($command['table']) . " " . $condition_string;
1265                                 $this->logger->debug($this->replaceParameters($sql, $conditions));
1266
1267                                 if (!$this->e($sql, $conditions)) {
1268                                         if ($do_transaction) {
1269                                                 $this->rollback();
1270                                         }
1271                                         return false;
1272                                 }
1273                         } else {
1274                                 $key_table     = $command['table'];
1275                                 $key_condition = array_keys($command['conditions'])[0];
1276                                 $value         = array_values($command['conditions'])[0];
1277
1278                                 // Split the SQL queries in chunks of 100 values
1279                                 // We do the $i stuff here to make the code better readable
1280                                 $i = isset($counter[$key_table][$key_condition]) ? $counter[$key_table][$key_condition] : 0;
1281                                 if (isset($compacted[$key_table][$key_condition][$i]) && count($compacted[$key_table][$key_condition][$i]) > 100) {
1282                                         ++$i;
1283                                 }
1284
1285                                 $compacted[$key_table][$key_condition][$i][$value] = $value;
1286                                 $counter[$key_table][$key_condition]               = $i;
1287                         }
1288                 }
1289                 foreach ($compacted AS $table => $values) {
1290                         foreach ($values AS $field => $field_value_list) {
1291                                 foreach ($field_value_list AS $field_values) {
1292                                         $sql = "DELETE FROM " . DBA::quoteIdentifier($table) . " WHERE " . DBA::quoteIdentifier($field) . " IN (" .
1293                                                substr(str_repeat("?, ", count($field_values)), 0, -2) . ");";
1294
1295                                         $this->logger->debug($this->replaceParameters($sql, $field_values));
1296
1297                                         if (!$this->e($sql, $field_values)) {
1298                                                 if ($do_transaction) {
1299                                                         $this->rollback();
1300                                                 }
1301                                                 return false;
1302                                         }
1303                                 }
1304                         }
1305                 }
1306                 if ($do_transaction) {
1307                         $this->commit();
1308                 }
1309                 return true;
1310         }
1311
1312         /**
1313          * Updates rows
1314          *
1315          * Updates rows in the database. When $old_fields is set to an array,
1316          * the system will only do an update if the fields in that array changed.
1317          *
1318          * Attention:
1319          * Only the values in $old_fields are compared.
1320          * This is an intentional behaviour.
1321          *
1322          * Example:
1323          * We include the timestamp field in $fields but not in $old_fields.
1324          * Then the row will only get the new timestamp when the other fields had changed.
1325          *
1326          * When $old_fields is set to a boolean value the system will do this compare itself.
1327          * When $old_fields is set to "true" the system will do an insert if the row doesn't exists.
1328          *
1329          * Attention:
1330          * Only set $old_fields to a boolean value when you are sure that you will update a single row.
1331          * When you set $old_fields to "true" then $fields must contain all relevant fields!
1332          *
1333          * @param string|array  $table      Table name or array [schema => table]
1334          * @param array         $fields     contains the fields that are updated
1335          * @param array         $condition  condition array with the key values
1336          * @param array|boolean $old_fields array with the old field values that are about to be replaced (true = update on duplicate)
1337          *
1338          * @return boolean was the update successfull?
1339          * @throws \Exception
1340          */
1341         public function update($table, $fields, $condition, $old_fields = [])
1342         {
1343                 if (empty($table) || empty($fields) || empty($condition)) {
1344                         $this->logger->info('Table, fields and condition have to be set');
1345                         return false;
1346                 }
1347
1348                 if (is_bool($old_fields)) {
1349                         $do_insert = $old_fields;
1350
1351                         $old_fields = $this->selectFirst($table, [], $condition);
1352
1353                         if (is_bool($old_fields)) {
1354                                 if ($do_insert) {
1355                                         $values = array_merge($condition, $fields);
1356                                         return $this->insert($table, $values, $do_insert);
1357                                 }
1358                                 $old_fields = [];
1359                         }
1360                 }
1361
1362                 foreach ($old_fields AS $fieldname => $content) {
1363                         if (isset($fields[$fieldname]) && !is_null($content) && ($fields[$fieldname] == $content)) {
1364                                 unset($fields[$fieldname]);
1365                         }
1366                 }
1367
1368                 if (count($fields) == 0) {
1369                         return true;
1370                 }
1371
1372                 $table_string = DBA::buildTableString($table);
1373
1374                 $condition_string = DBA::buildCondition($condition);
1375
1376                 $sql = "UPDATE " . $table_string . " SET "
1377                         . implode(" = ?, ", array_map([DBA::class, 'quoteIdentifier'], array_keys($fields))) . " = ?"
1378                         . $condition_string;
1379
1380                 // Combines the updated fields parameter values with the condition parameter values
1381                 $params  = array_merge(array_values($fields), $condition);
1382
1383                 return $this->e($sql, $params);
1384         }
1385
1386         /**
1387          * Retrieve a single record from a table and returns it in an associative array
1388          *
1389          * @param string|array $table
1390          * @param array        $fields
1391          * @param array        $condition
1392          * @param array        $params
1393          *
1394          * @return bool|array
1395          * @throws \Exception
1396          * @see   $this->select
1397          */
1398         public function selectFirst($table, array $fields = [], array $condition = [], $params = [])
1399         {
1400                 $params['limit'] = 1;
1401                 $result          = $this->select($table, $fields, $condition, $params);
1402
1403                 if (is_bool($result)) {
1404                         return $result;
1405                 } else {
1406                         $row = $this->fetch($result);
1407                         $this->close($result);
1408                         return $row;
1409                 }
1410         }
1411
1412         /**
1413          * Select rows from a table and fills an array with the data
1414          *
1415          * @param string|array $table     Table name or array [schema => table]
1416          * @param array        $fields    Array of selected fields, empty for all
1417          * @param array        $condition Array of fields for condition
1418          * @param array        $params    Array of several parameters
1419          *
1420          * @return array Data array
1421          * @throws \Exception
1422          * @see   self::select
1423          */
1424         public function selectToArray($table, array $fields = [], array $condition = [], array $params = [])
1425         {
1426                 return $this->toArray($this->select($table, $fields, $condition, $params));
1427         }
1428
1429         /**
1430          * Select rows from a table
1431          *
1432          * @param string|array $table     Table name or array [schema => table]
1433          * @param array        $fields    Array of selected fields, empty for all
1434          * @param array        $condition Array of fields for condition
1435          * @param array        $params    Array of several parameters
1436          *
1437          * @return boolean|object
1438          *
1439          * Example:
1440          * $table = "item";
1441          * $fields = array("id", "uri", "uid", "network");
1442          *
1443          * $condition = array("uid" => 1, "network" => 'dspr');
1444          * or:
1445          * $condition = array("`uid` = ? AND `network` IN (?, ?)", 1, 'dfrn', 'dspr');
1446          *
1447          * $params = array("order" => array("id", "received" => true), "limit" => 10);
1448          *
1449          * $data = DBA::select($table, $fields, $condition, $params);
1450          * @throws \Exception
1451          */
1452         public function select($table, array $fields = [], array $condition = [], array $params = [])
1453         {
1454                 if (empty($table)) {
1455                         return false;
1456                 }
1457
1458                 if (count($fields) > 0) {
1459                         $select_string = implode(', ', array_map([DBA::class, 'quoteIdentifier'], $fields));
1460                 } else {
1461                         $select_string = '*';
1462                 }
1463
1464                 $table_string = DBA::buildTableString($table);
1465
1466                 $condition_string = DBA::buildCondition($condition);
1467
1468                 $param_string = DBA::buildParameter($params);
1469
1470                 $sql = "SELECT " . $select_string . " FROM " . $table_string . $condition_string . $param_string;
1471
1472                 $result = $this->p($sql, $condition);
1473
1474                 return $result;
1475         }
1476
1477         /**
1478          * Counts the rows from a table satisfying the provided condition
1479          *
1480          * @param string|array $table     Table name or array [schema => table]
1481          * @param array        $condition Array of fields for condition
1482          * @param array        $params    Array of several parameters
1483          *
1484          * @return int
1485          *
1486          * Example:
1487          * $table = "item";
1488          *
1489          * $condition = ["uid" => 1, "network" => 'dspr'];
1490          * or:
1491          * $condition = ["`uid` = ? AND `network` IN (?, ?)", 1, 'dfrn', 'dspr'];
1492          *
1493          * $count = DBA::count($table, $condition);
1494          * @throws \Exception
1495          */
1496         public function count($table, array $condition = [], array $params = [])
1497         {
1498                 if (empty($table)) {
1499                         return false;
1500                 }
1501
1502                 $table_string = DBA::buildTableString($table);
1503
1504                 $condition_string = DBA::buildCondition($condition);
1505
1506                 if (empty($params['expression'])) {
1507                         $expression = '*';
1508                 } elseif (!empty($params['distinct'])) {
1509                         $expression = "DISTINCT " . DBA::quoteIdentifier($params['expression']);
1510                 } else {
1511                         $expression = DBA::quoteIdentifier($params['expression']);
1512                 }
1513
1514                 $sql = "SELECT COUNT(" . $expression . ") AS `count` FROM " . $table_string . $condition_string;
1515
1516                 $row = $this->fetchFirst($sql, $condition);
1517
1518                 return $row['count'];
1519         }
1520
1521         /**
1522          * Fills an array with data from a query
1523          *
1524          * @param object $stmt statement object
1525          * @param bool   $do_close
1526          *
1527          * @return array Data array
1528          */
1529         public function toArray($stmt, $do_close = true)
1530         {
1531                 if (is_bool($stmt)) {
1532                         return [];
1533                 }
1534
1535                 $data = [];
1536                 while ($row = $this->fetch($stmt)) {
1537                         $data[] = $row;
1538                 }
1539
1540                 if ($do_close) {
1541                         $this->close($stmt);
1542                 }
1543
1544                 return $data;
1545         }
1546
1547         /**
1548          * Returns the error number of the last query
1549          *
1550          * @return string Error number (0 if no error)
1551          */
1552         public function errorNo()
1553         {
1554                 return $this->errorno;
1555         }
1556
1557         /**
1558          * Returns the error message of the last query
1559          *
1560          * @return string Error message ('' if no error)
1561          */
1562         public function errorMessage()
1563         {
1564                 return $this->error;
1565         }
1566
1567         /**
1568          * Closes the current statement
1569          *
1570          * @param object $stmt statement object
1571          *
1572          * @return boolean was the close successful?
1573          */
1574         public function close($stmt)
1575         {
1576
1577                 $stamp1 = microtime(true);
1578
1579                 if (!is_object($stmt)) {
1580                         return false;
1581                 }
1582
1583                 switch ($this->driver) {
1584                         case 'pdo':
1585                                 $ret = $stmt->closeCursor();
1586                                 break;
1587                         case 'mysqli':
1588                                 // MySQLi offers both a mysqli_stmt and a mysqli_result class.
1589                                 // We should be careful not to assume the object type of $stmt
1590                                 // because DBA::p() has been able to return both types.
1591                                 if ($stmt instanceof mysqli_stmt) {
1592                                         $stmt->free_result();
1593                                         $ret = $stmt->close();
1594                                 } elseif ($stmt instanceof mysqli_result) {
1595                                         $stmt->free();
1596                                         $ret = true;
1597                                 } else {
1598                                         $ret = false;
1599                                 }
1600                                 break;
1601                 }
1602
1603                 $this->profiler->saveTimestamp($stamp1, 'database', System::callstack());
1604
1605                 return $ret;
1606         }
1607
1608         /**
1609          * Return a list of database processes
1610          *
1611          * @return array
1612          *      'list' => List of processes, separated in their different states
1613          *      'amount' => Number of concurrent database processes
1614          * @throws \Exception
1615          */
1616         public function processlist()
1617         {
1618                 $ret  = $this->p("SHOW PROCESSLIST");
1619                 $data = $this->toArray($ret);
1620
1621                 $processes = 0;
1622                 $states    = [];
1623                 foreach ($data as $process) {
1624                         $state = trim($process["State"]);
1625
1626                         // Filter out all non blocking processes
1627                         if (!in_array($state, ["", "init", "statistics", "updating"])) {
1628                                 ++$states[$state];
1629                                 ++$processes;
1630                         }
1631                 }
1632
1633                 $statelist = "";
1634                 foreach ($states as $state => $usage) {
1635                         if ($statelist != "") {
1636                                 $statelist .= ", ";
1637                         }
1638                         $statelist .= $state . ": " . $usage;
1639                 }
1640                 return (["list" => $statelist, "amount" => $processes]);
1641         }
1642
1643         /**
1644          * Checks if $array is a filled array with at least one entry.
1645          *
1646          * @param mixed $array A filled array with at least one entry
1647          *
1648          * @return boolean Whether $array is a filled array or an object with rows
1649          */
1650         public function isResult($array)
1651         {
1652                 // It could be a return value from an update statement
1653                 if (is_bool($array)) {
1654                         return $array;
1655                 }
1656
1657                 if (is_object($array)) {
1658                         return $this->numRows($array) > 0;
1659                 }
1660
1661                 return (is_array($array) && (count($array) > 0));
1662         }
1663
1664         /**
1665          * Callback function for "esc_array"
1666          *
1667          * @param mixed   $value         Array value
1668          * @param string  $key           Array key
1669          * @param boolean $add_quotation add quotation marks for string values
1670          *
1671          * @return void
1672          */
1673         private function escapeArrayCallback(&$value, $key, $add_quotation)
1674         {
1675                 if (!$add_quotation) {
1676                         if (is_bool($value)) {
1677                                 $value = ($value ? '1' : '0');
1678                         } else {
1679                                 $value = $this->escape($value);
1680                         }
1681                         return;
1682                 }
1683
1684                 if (is_bool($value)) {
1685                         $value = ($value ? 'true' : 'false');
1686                 } elseif (is_float($value) || is_integer($value)) {
1687                         $value = (string)$value;
1688                 } else {
1689                         $value = "'" . $this->escape($value) . "'";
1690                 }
1691         }
1692
1693         /**
1694          * Escapes a whole array
1695          *
1696          * @param mixed   $arr           Array with values to be escaped
1697          * @param boolean $add_quotation add quotation marks for string values
1698          *
1699          * @return void
1700          */
1701         public function escapeArray(&$arr, $add_quotation = false)
1702         {
1703                 array_walk($arr, [$this, 'escapeArrayCallback'], $add_quotation);
1704         }
1705 }