src/Database/DBA.php

   1 <?php
   2
   3 namespace Friendica\Database;
   4
   5 // Do not use Core\Config in this class at risk of infinite loop.
   6 // Please use App->getConfigVariable() instead.
   7 //use Friendica\Core\Config;
   8
   9 use Friendica\Core\System;
  10 use Friendica\Util\DateTimeFormat;
  11 use mysqli;
  12 use PDO;
  13 use PDOException;
  14 use PDOStatement;
  15
  16 /**
  17  * @class MySQL database class
  18  *
  19  * This class is for the low level database stuff that does driver specific things.
  20  */
  21 class DBA
  22 {
  23         public static $connected = false;
  24
  25         private static $server_info = '';
  26         private static $db;
  27         private static $driver;
  28         private static $error = false;
  29         private static $errorno = 0;
  30         private static $affected_rows = 0;
  31         private static $in_transaction = false;
  32         private static $in_retrial = false;
  33         private static $relation = [];
  34         private static $db_serveraddr = '';
  35         private static $db_user = '';
  36         private static $db_pass = '';
  37         private static $db_name = '';
  38         private static $db_charset = '';
  39
  40         public static function connect($serveraddr, $user, $pass, $db, $charset = null)
  41         {
  42                 if (!is_null(self::$db) && self::connected()) {
  43                         return true;
  44                 }
  45
  46                 // We are storing these values for being able to perform a reconnect
  47                 self::$db_serveraddr = $serveraddr;
  48                 self::$db_user = $user;
  49                 self::$db_pass = $pass;
  50                 self::$db_name = $db;
  51                 self::$db_charset = $charset;
  52
  53                 $port = 0;
  54                 $serveraddr = trim($serveraddr);
  55
  56                 $serverdata = explode(':', $serveraddr);
  57                 $server = $serverdata[0];
  58
  59                 if (count($serverdata) > 1) {
  60                         $port = trim($serverdata[1]);
  61                 }
  62
  63                 $server = trim($server);
  64                 $user = trim($user);
  65                 $pass = trim($pass);
  66                 $db = trim($db);
  67                 $charset = trim($charset);
  68
  69                 if (!(strlen($server) && strlen($user))) {
  70                         return false;
  71                 }
  72
  73                 if (class_exists('\PDO') && in_array('mysql', PDO::getAvailableDrivers())) {
  74                         self::$driver = 'pdo';
  75                         $connect = "mysql:host=".$server.";dbname=".$db;
  76
  77                         if ($port > 0) {
  78                                 $connect .= ";port=".$port;
  79                         }
  80
  81                         if ($charset) {
  82                                 $connect .= ";charset=".$charset;
  83                         }
  84
  85                         try {
  86                                 self::$db = @new PDO($connect, $user, $pass);
  87                                 self::$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
  88                                 self::$connected = true;
  89                         } catch (PDOException $e) {
  90                         }
  91                 }
  92
  93                 if (!self::$connected && class_exists('\mysqli')) {
  94                         self::$driver = 'mysqli';
  95
  96                         if ($port > 0) {
  97                                 self::$db = @new mysqli($server, $user, $pass, $db, $port);
  98                         } else {
  99                                 self::$db = @new mysqli($server, $user, $pass, $db);
 100                         }
 101
 102                         if (!mysqli_connect_errno()) {
 103                                 self::$connected = true;
 104
 105                                 if ($charset) {
 106                                         self::$db->set_charset($charset);
 107                                 }
 108                         }
 109                 }
 110
 111                 // No suitable SQL driver was found.
 112                 if (!self::$connected) {
 113                         self::$driver = null;
 114                         self::$db = null;
 115                 }
 116
 117                 return self::$connected;
 118         }
 119
 120         /**
 121          * Disconnects the current database connection
 122          */
 123         public static function disconnect()
 124         {
 125                 if (is_null(self::$db)) {
 126                         return;
 127                 }
 128
 129                 switch (self::$driver) {
 130                         case 'pdo':
 131                                 self::$db = null;
 132                                 break;
 133                         case 'mysqli':
 134                                 self::$db->close();
 135                                 self::$db = null;
 136                                 break;
 137                 }
 138         }
 139
 140         /**
 141          * Perform a reconnect of an existing database connection
 142          */
 143         public static function reconnect() {
 144                 self::disconnect();
 145
 146                 $ret = self::connect(self::$db_serveraddr, self::$db_user, self::$db_pass, self::$db_name, self::$db_charset);
 147                 return $ret;
 148         }
 149
 150         /**
 151          * Return the database object.
 152          * @return PDO|mysqli
 153          */
 154         public static function get_db()
 155         {
 156                 return self::$db;
 157         }
 158
 159         /**
 160          * @brief Returns the MySQL server version string
 161          *
 162          * This function discriminate between the deprecated mysql API and the current
 163          * object-oriented mysqli API. Example of returned string: 5.5.46-0+deb8u1
 164          *
 165          * @return string
 166          */
 167         public static function server_info() {
 168                 if (self::$server_info == '') {
 169                         switch (self::$driver) {
 170                                 case 'pdo':
 171                                         self::$server_info = self::$db->getAttribute(PDO::ATTR_SERVER_VERSION);
 172                                         break;
 173                                 case 'mysqli':
 174                                         self::$server_info = self::$db->server_info;
 175                                         break;
 176                         }
 177                 }
 178                 return self::$server_info;
 179         }
 180
 181         /**
 182          * @brief Returns the selected database name
 183          *
 184          * @return string
 185          */
 186         public static function database_name() {
 187                 $ret = self::p("SELECT DATABASE() AS `db`");
 188                 $data = self::inArray($ret);
 189                 return $data[0]['db'];
 190         }
 191
 192         /**
 193          * @brief Analyze a database query and log this if some conditions are met.
 194          *
 195          * @param string $query The database query that will be analyzed
 196          */
 197         private static function logIndex($query) {
 198                 $a = get_app();
 199
 200                 if (!$a->getConfigVariable('system', 'db_log_index')) {
 201                         return;
 202                 }
 203
 204                 // Don't explain an explain statement
 205                 if (strtolower(substr($query, 0, 7)) == "explain") {
 206                         return;
 207                 }
 208
 209                 // Only do the explain on "select", "update" and "delete"
 210                 if (!in_array(strtolower(substr($query, 0, 6)), ["select", "update", "delete"])) {
 211                         return;
 212                 }
 213
 214                 $r = self::p("EXPLAIN ".$query);
 215                 if (!DBM::is_result($r)) {
 216                         return;
 217                 }
 218
 219                 $watchlist = explode(',', $a->getConfigVariable('system', 'db_log_index_watch'));
 220                 $blacklist = explode(',', $a->getConfigVariable('system', 'db_log_index_blacklist'));
 221
 222                 while ($row = self::fetch($r)) {
 223                         if ((intval($a->getConfigVariable('system', 'db_loglimit_index')) > 0)) {
 224                                 $log = (in_array($row['key'], $watchlist) &&
 225                                         ($row['rows'] >= intval($a->getConfigVariable('system', 'db_loglimit_index'))));
 226                         } else {
 227                                 $log = false;
 228                         }
 229
 230                         if ((intval($a->getConfigVariable('system', 'db_loglimit_index_high')) > 0) && ($row['rows'] >= intval($a->getConfigVariable('system', 'db_loglimit_index_high')))) {
 231                                 $log = true;
 232                         }
 233
 234                         if (in_array($row['key'], $blacklist) || ($row['key'] == "")) {
 235                                 $log = false;
 236                         }
 237
 238                         if ($log) {
 239                                 $backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
 240                                 @file_put_contents($a->getConfigVariable('system', 'db_log_index'), DateTimeFormat::utcNow()."\t".
 241                                                 $row['key']."\t".$row['rows']."\t".$row['Extra']."\t".
 242                                                 basename($backtrace[1]["file"])."\t".
 243                                                 $backtrace[1]["line"]."\t".$backtrace[2]["function"]."\t".
 244                                                 substr($query, 0, 2000)."\n", FILE_APPEND);
 245                         }
 246                 }
 247         }
 248
 249         public static function escape($str) {
 250                 switch (self::$driver) {
 251                         case 'pdo':
 252                                 return substr(@self::$db->quote($str, PDO::PARAM_STR), 1, -1);
 253                         case 'mysqli':
 254                                 return @self::$db->real_escape_string($str);
 255                 }
 256         }
 257
 258         public static function connected() {
 259                 $connected = false;
 260
 261                 if (is_null(self::$db)) {
 262                         return false;
 263                 }
 264
 265                 switch (self::$driver) {
 266                         case 'pdo':
 267                                 $r = self::p("SELECT 1");
 268                                 if (DBM::is_result($r)) {
 269                                         $row = self::inArray($r);
 270                                         $connected = ($row[0]['1'] == '1');
 271                                 }
 272                                 break;
 273                         case 'mysqli':
 274                                 $connected = self::$db->ping();
 275                                 break;
 276                 }
 277                 return $connected;
 278         }
 279
 280         /**
 281          * @brief Replaces ANY_VALUE() function by MIN() function,
 282          *  if the database server does not support ANY_VALUE().
 283          *
 284          * Considerations for Standard SQL, or MySQL with ONLY_FULL_GROUP_BY (default since 5.7.5).
 285          * ANY_VALUE() is available from MySQL 5.7.5 https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html
 286          * A standard fall-back is to use MIN().
 287          *
 288          * @param string $sql An SQL string without the values
 289          * @return string The input SQL string modified if necessary.
 290          */
 291         public static function any_value_fallback($sql) {
 292                 $server_info = self::server_info();
 293                 if (version_compare($server_info, '5.7.5', '<') ||
 294                         (stripos($server_info, 'MariaDB') !== false)) {
 295                         $sql = str_ireplace('ANY_VALUE(', 'MIN(', $sql);
 296                 }
 297                 return $sql;
 298         }
 299
 300         /**
 301          * @brief beautifies the query - useful for "SHOW PROCESSLIST"
 302          *
 303          * This is safe when we bind the parameters later.
 304          * The parameter values aren't part of the SQL.
 305          *
 306          * @param string $sql An SQL string without the values
 307          * @return string The input SQL string modified if necessary.
 308          */
 309         public static function clean_query($sql) {
 310                 $search = ["\t", "\n", "\r", "  "];
 311                 $replace = [' ', ' ', ' ', ' '];
 312                 do {
 313                         $oldsql = $sql;
 314                         $sql = str_replace($search, $replace, $sql);
 315                 } while ($oldsql != $sql);
 316
 317                 return $sql;
 318         }
 319
 320
 321         /**
 322          * @brief Replaces the ? placeholders with the parameters in the $args array
 323          *
 324          * @param string $sql SQL query
 325          * @param array $args The parameters that are to replace the ? placeholders
 326          * @return string The replaced SQL query
 327          */
 328         private static function replaceParameters($sql, $args) {
 329                 $offset = 0;
 330                 foreach ($args AS $param => $value) {
 331                         if (is_int($args[$param]) || is_float($args[$param])) {
 332                                 $replace = intval($args[$param]);
 333                         } else {
 334                                 $replace = "'".self::escape($args[$param])."'";
 335                         }
 336
 337                         $pos = strpos($sql, '?', $offset);
 338                         if ($pos !== false) {
 339                                 $sql = substr_replace($sql, $replace, $pos, 1);
 340                         }
 341                         $offset = $pos + strlen($replace);
 342                 }
 343                 return $sql;
 344         }
 345
 346         /**
 347          * @brief Convert parameter array to an universal form
 348          * @param array $args Parameter array
 349          * @return array universalized parameter array
 350          */
 351         private static function getParam($args) {
 352                 unset($args[0]);
 353
 354                 // When the second function parameter is an array then use this as the parameter array
 355                 if ((count($args) > 0) && (is_array($args[1]))) {
 356                         return $args[1];
 357                 } else {
 358                         return $args;
 359                 }
 360         }
 361
 362         /**
 363          * @brief Executes a prepared statement that returns data
 364          * @usage Example: $r = p("SELECT * FROM `item` WHERE `guid` = ?", $guid);
 365          *
 366          * Please only use it with complicated queries.
 367          * For all regular queries please use dba::select or dba::exists
 368          *
 369          * @param string $sql SQL statement
 370          * @return bool|object statement object or result object
 371          */
 372         public static function p($sql) {
 373                 $a = get_app();
 374
 375                 $stamp1 = microtime(true);
 376
 377                 $params = self::getParam(func_get_args());
 378
 379                 // Renumber the array keys to be sure that they fit
 380                 $i = 0;
 381                 $args = [];
 382                 foreach ($params AS $param) {
 383                         // Avoid problems with some MySQL servers and boolean values. See issue #3645
 384                         if (is_bool($param)) {
 385                                 $param = (int)$param;
 386                         }
 387                         $args[++$i] = $param;
 388                 }
 389
 390                 if (!self::$connected) {
 391                         return false;
 392                 }
 393
 394                 if ((substr_count($sql, '?') != count($args)) && (count($args) > 0)) {
 395                         // Question: Should we continue or stop the query here?
 396                         logger('Parameter mismatch. Query "'.$sql.'" - Parameters '.print_r($args, true), LOGGER_DEBUG);
 397                 }
 398
 399                 $sql = self::clean_query($sql);
 400                 $sql = self::any_value_fallback($sql);
 401
 402                 $orig_sql = $sql;
 403
 404                 if ($a->getConfigValue('system', 'db_callstack')) {
 405                         $sql = "/*".System::callstack()." */ ".$sql;
 406                 }
 407
 408                 self::$error = '';
 409                 self::$errorno = 0;
 410                 self::$affected_rows = 0;
 411
 412                 // We have to make some things different if this function is called from "e"
 413                 $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
 414
 415                 if (isset($trace[1])) {
 416                         $called_from = $trace[1];
 417                 } else {
 418                         // We use just something that is defined to avoid warnings
 419                         $called_from = $trace[0];
 420                 }
 421                 // We are having an own error logging in the function "e"
 422                 $called_from_e = ($called_from['function'] == 'e');
 423
 424                 switch (self::$driver) {
 425                         case 'pdo':
 426                                 // If there are no arguments we use "query"
 427                                 if (count($args) == 0) {
 428                                         if (!$retval = self::$db->query($sql)) {
 429                                                 $errorInfo = self::$db->errorInfo();
 430                                                 self::$error = $errorInfo[2];
 431                                                 self::$errorno = $errorInfo[1];
 432                                                 $retval = false;
 433                                                 break;
 434                                         }
 435                                         self::$affected_rows = $retval->rowCount();
 436                                         break;
 437                                 }
 438
 439                                 if (!$stmt = self::$db->prepare($sql)) {
 440                                         $errorInfo = self::$db->errorInfo();
 441                                         self::$error = $errorInfo[2];
 442                                         self::$errorno = $errorInfo[1];
 443                                         $retval = false;
 444                                         break;
 445                                 }
 446
 447                                 foreach ($args AS $param => $value) {
 448                                         if (is_int($args[$param])) {
 449                                                 $data_type = PDO::PARAM_INT;
 450                                         } else {
 451                                                 $data_type = PDO::PARAM_STR;
 452                                         }
 453                                         $stmt->bindParam($param, $args[$param], $data_type);
 454                                 }
 455
 456                                 if (!$stmt->execute()) {
 457                                         $errorInfo = $stmt->errorInfo();
 458                                         self::$error = $errorInfo[2];
 459                                         self::$errorno = $errorInfo[1];
 460                                         $retval = false;
 461                                 } else {
 462                                         $retval = $stmt;
 463                                         self::$affected_rows = $retval->rowCount();
 464                                 }
 465                                 break;
 466                         case 'mysqli':
 467                                 // There are SQL statements that cannot be executed with a prepared statement
 468                                 $parts = explode(' ', $orig_sql);
 469                                 $command = strtolower($parts[0]);
 470                                 $can_be_prepared = in_array($command, ['select', 'update', 'insert', 'delete']);
 471
 472                                 // The fallback routine is called as well when there are no arguments
 473                                 if (!$can_be_prepared || (count($args) == 0)) {
 474                                         $retval = self::$db->query(self::replaceParameters($sql, $args));
 475                                         if (self::$db->errno) {
 476                                                 self::$error = self::$db->error;
 477                                                 self::$errorno = self::$db->errno;
 478                                                 $retval = false;
 479                                         } else {
 480                                                 if (isset($retval->num_rows)) {
 481                                                         self::$affected_rows = $retval->num_rows;
 482                                                 } else {
 483                                                         self::$affected_rows = self::$db->affected_rows;
 484                                                 }
 485                                         }
 486                                         break;
 487                                 }
 488
 489                                 $stmt = self::$db->stmt_init();
 490
 491                                 if (!$stmt->prepare($sql)) {
 492                                         self::$error = $stmt->error;
 493                                         self::$errorno = $stmt->errno;
 494                                         $retval = false;
 495                                         break;
 496                                 }
 497
 498                                 $param_types = '';
 499                                 $values = [];
 500                                 foreach ($args AS $param => $value) {
 501                                         if (is_int($args[$param])) {
 502                                                 $param_types .= 'i';
 503                                         } elseif (is_float($args[$param])) {
 504                                                 $param_types .= 'd';
 505                                         } elseif (is_string($args[$param])) {
 506                                                 $param_types .= 's';
 507                                         } else {
 508                                                 $param_types .= 'b';
 509                                         }
 510                                         $values[] = &$args[$param];
 511                                 }
 512
 513                                 if (count($values) > 0) {
 514                                         array_unshift($values, $param_types);
 515                                         call_user_func_array([$stmt, 'bind_param'], $values);
 516                                 }
 517
 518                                 if (!$stmt->execute()) {
 519                                         self::$error = self::$db->error;
 520                                         self::$errorno = self::$db->errno;
 521                                         $retval = false;
 522                                 } else {
 523                                         $stmt->store_result();
 524                                         $retval = $stmt;
 525                                         self::$affected_rows = $retval->affected_rows;
 526                                 }
 527                                 break;
 528                 }
 529
 530                 // We are having an own error logging in the function "e"
 531                 if ((self::$errorno != 0) && !$called_from_e) {
 532                         // We have to preserve the error code, somewhere in the logging it get lost
 533                         $error = self::$error;
 534                         $errorno = self::$errorno;
 535
 536                         logger('DB Error '.self::$errorno.': '.self::$error."\n".
 537                                 System::callstack(8)."\n".self::replaceParameters($sql, $args));
 538
 539                         // On a lost connection we try to reconnect - but only once.
 540                         if ($errorno == 2006) {
 541                                 if (self::$in_retrial || !self::reconnect()) {
 542                                         // It doesn't make sense to continue when the database connection was lost
 543                                         if (self::$in_retrial) {
 544                                                 logger('Giving up retrial because of database error '.$errorno.': '.$error);
 545                                         } else {
 546                                                 logger("Couldn't reconnect after database error ".$errorno.': '.$error);
 547                                         }
 548                                         exit(1);
 549                                 } else {
 550                                         // We try it again
 551                                         logger('Reconnected after database error '.$errorno.': '.$error);
 552                                         self::$in_retrial = true;
 553                                         $ret = self::p($sql, $args);
 554                                         self::$in_retrial = false;
 555                                         return $ret;
 556                                 }
 557                         }
 558
 559                         self::$error = $error;
 560                         self::$errorno = $errorno;
 561                 }
 562
 563                 $a->save_timestamp($stamp1, 'database');
 564
 565                 if ($a->getConfigValue('system', 'db_log')) {
 566                         $stamp2 = microtime(true);
 567                         $duration = (float)($stamp2 - $stamp1);
 568
 569                         if (($duration > $a->getConfigValue('system', 'db_loglimit'))) {
 570                                 $duration = round($duration, 3);
 571                                 $backtrace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
 572
 573                                 @file_put_contents($a->getConfigValue('system', 'db_log'), DateTimeFormat::utcNow()."\t".$duration."\t".
 574                                                 basename($backtrace[1]["file"])."\t".
 575                                                 $backtrace[1]["line"]."\t".$backtrace[2]["function"]."\t".
 576                                                 substr(self::replaceParameters($sql, $args), 0, 2000)."\n", FILE_APPEND);
 577                         }
 578                 }
 579                 return $retval;
 580         }
 581
 582         /**
 583          * @brief Executes a prepared statement like UPDATE or INSERT that doesn't return data
 584          *
 585          * Please use dba::delete, dba::insert, dba::update, ... instead
 586          *
 587          * @param string $sql SQL statement
 588          * @return boolean Was the query successfull? False is returned only if an error occurred
 589          */
 590         public static function e($sql) {
 591                 $a = get_app();
 592
 593                 $stamp = microtime(true);
 594
 595                 $params = self::getParam(func_get_args());
 596
 597                 // In a case of a deadlock we are repeating the query 20 times
 598                 $timeout = 20;
 599
 600                 do {
 601                         $stmt = self::p($sql, $params);
 602
 603                         if (is_bool($stmt)) {
 604                                 $retval = $stmt;
 605                         } elseif (is_object($stmt)) {
 606                                 $retval = true;
 607                         } else {
 608                                 $retval = false;
 609                         }
 610
 611                         self::close($stmt);
 612
 613                 } while ((self::$errorno == 1213) && (--$timeout > 0));
 614
 615                 if (self::$errorno != 0) {
 616                         // We have to preserve the error code, somewhere in the logging it get lost
 617                         $error = self::$error;
 618                         $errorno = self::$errorno;
 619
 620                         logger('DB Error '.self::$errorno.': '.self::$error."\n".
 621                                 System::callstack(8)."\n".self::replaceParameters($sql, $params));
 622
 623                         // On a lost connection we simply quit.
 624                         // A reconnect like in self::p could be dangerous with modifications
 625                         if ($errorno == 2006) {
 626                                 logger('Giving up because of database error '.$errorno.': '.$error);
 627                                 exit(1);
 628                         }
 629
 630                         self::$error = $error;
 631                         self::$errorno = $errorno;
 632                 }
 633
 634                 $a->save_timestamp($stamp, "database_write");
 635
 636                 return $retval;
 637         }
 638
 639         /**
 640          * @brief Check if data exists
 641          *
 642          * @param string $table Table name
 643          * @param array $condition array of fields for condition
 644          *
 645          * @return boolean Are there rows for that condition?
 646          */
 647         public static function exists($table, $condition) {
 648                 if (empty($table)) {
 649                         return false;
 650                 }
 651
 652                 $fields = [];
 653
 654                 if (empty($condition)) {
 655                         return DBStructure::existsTable($table);
 656                 }
 657
 658                 reset($condition);
 659                 $first_key = key($condition);
 660                 if (!is_int($first_key)) {
 661                         $fields = [$first_key];
 662                 }
 663
 664                 $stmt = self::select($table, $fields, $condition, ['limit' => 1]);
 665
 666                 if (is_bool($stmt)) {
 667                         $retval = $stmt;
 668                 } else {
 669                         $retval = (self::num_rows($stmt) > 0);
 670                 }
 671
 672                 self::close($stmt);
 673
 674                 return $retval;
 675         }
 676
 677         /**
 678          * Fetches the first row
 679          *
 680          * Please use dba::selectFirst or dba::exists whenever this is possible.
 681          *
 682          * @brief Fetches the first row
 683          * @param string $sql SQL statement
 684          * @return array first row of query
 685          */
 686         public static function fetch_first($sql) {
 687                 $params = self::getParam(func_get_args());
 688
 689                 $stmt = self::p($sql, $params);
 690
 691                 if (is_bool($stmt)) {
 692                         $retval = $stmt;
 693                 } else {
 694                         $retval = self::fetch($stmt);
 695                 }
 696
 697                 self::close($stmt);
 698
 699                 return $retval;
 700         }
 701
 702         /**
 703          * @brief Returns the number of affected rows of the last statement
 704          *
 705          * @return int Number of rows
 706          */
 707         public static function affectedRows() {
 708                 return self::$affected_rows;
 709         }
 710
 711         /**
 712          * @brief Returns the number of columns of a statement
 713          *
 714          * @param object Statement object
 715          * @return int Number of columns
 716          */
 717         public static function columnCount($stmt) {
 718                 if (!is_object($stmt)) {
 719                         return 0;
 720                 }
 721                 switch (self::$driver) {
 722                         case 'pdo':
 723                                 return $stmt->columnCount();
 724                         case 'mysqli':
 725                                 return $stmt->field_count;
 726                 }
 727                 return 0;
 728         }
 729         /**
 730          * @brief Returns the number of rows of a statement
 731          *
 732          * @param PDOStatement|mysqli_result|mysqli_stmt Statement object
 733          * @return int Number of rows
 734          */
 735         public static function num_rows($stmt) {
 736                 if (!is_object($stmt)) {
 737                         return 0;
 738                 }
 739                 switch (self::$driver) {
 740                         case 'pdo':
 741                                 return $stmt->rowCount();
 742                         case 'mysqli':
 743                                 return $stmt->num_rows;
 744                 }
 745                 return 0;
 746         }
 747
 748         /**
 749          * @brief Fetch a single row
 750          *
 751          * @param mixed $stmt statement object
 752          * @return array current row
 753          */
 754         public static function fetch($stmt) {
 755                 $a = get_app();
 756
 757                 $stamp1 = microtime(true);
 758
 759                 $columns = [];
 760
 761                 if (!is_object($stmt)) {
 762                         return false;
 763                 }
 764
 765                 switch (self::$driver) {
 766                         case 'pdo':
 767                                 $columns = $stmt->fetch(PDO::FETCH_ASSOC);
 768                                 break;
 769                         case 'mysqli':
 770                                 if (get_class($stmt) == 'mysqli_result') {
 771                                         $columns = $stmt->fetch_assoc();
 772                                         break;
 773                                 }
 774
 775                                 // This code works, but is slow
 776
 777                                 // Bind the result to a result array
 778                                 $cols = [];
 779
 780                                 $cols_num = [];
 781                                 for ($x = 0; $x < $stmt->field_count; $x++) {
 782                                         $cols[] = &$cols_num[$x];
 783                                 }
 784
 785                                 call_user_func_array([$stmt, 'bind_result'], $cols);
 786
 787                                 if (!$stmt->fetch()) {
 788                                         return false;
 789                                 }
 790
 791                                 // The slow part:
 792                                 // We need to get the field names for the array keys
 793                                 // It seems that there is no better way to do this.
 794                                 $result = $stmt->result_metadata();
 795                                 $fields = $result->fetch_fields();
 796
 797                                 foreach ($cols_num AS $param => $col) {
 798                                         $columns[$fields[$param]->name] = $col;
 799                                 }
 800                 }
 801
 802                 $a->save_timestamp($stamp1, 'database');
 803
 804                 return $columns;
 805         }
 806
 807         /**
 808          * @brief Insert a row into a table
 809          *
 810          * @param string $table Table name
 811          * @param array $param parameter array
 812          * @param bool $on_duplicate_update Do an update on a duplicate entry
 813          *
 814          * @return boolean was the insert successfull?
 815          */
 816         public static function insert($table, $param, $on_duplicate_update = false) {
 817
 818                 if (empty($table) || empty($param)) {
 819                         logger('Table and fields have to be set');
 820                         return false;
 821                 }
 822
 823                 $sql = "INSERT INTO `".self::escape($table)."` (`".implode("`, `", array_keys($param))."`) VALUES (".
 824                         substr(str_repeat("?, ", count($param)), 0, -2).")";
 825
 826                 if ($on_duplicate_update) {
 827                         $sql .= " ON DUPLICATE KEY UPDATE `".implode("` = ?, `", array_keys($param))."` = ?";
 828
 829                         $values = array_values($param);
 830                         $param = array_merge_recursive($values, $values);
 831                 }
 832
 833                 return self::e($sql, $param);
 834         }
 835
 836         /**
 837          * @brief Fetch the id of the last insert command
 838          *
 839          * @return integer Last inserted id
 840          */
 841         public static function lastInsertId() {
 842                 switch (self::$driver) {
 843                         case 'pdo':
 844                                 $id = self::$db->lastInsertId();
 845                                 break;
 846                         case 'mysqli':
 847                                 $id = self::$db->insert_id;
 848                                 break;
 849                 }
 850                 return $id;
 851         }
 852
 853         /**
 854          * @brief Locks a table for exclusive write access
 855          *
 856          * This function can be extended in the future to accept a table array as well.
 857          *
 858          * @param string $table Table name
 859          *
 860          * @return boolean was the lock successful?
 861          */
 862         public static function lock($table) {
 863                 // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
 864                 if (self::$driver == 'pdo') {
 865                         self::e("SET autocommit=0");
 866                         self::$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
 867                 } else {
 868                         self::$db->autocommit(false);
 869                 }
 870
 871                 $success = self::e("LOCK TABLES `".self::escape($table)."` WRITE");
 872
 873                 if (self::$driver == 'pdo') {
 874                         self::$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
 875                 }
 876
 877                 if (!$success) {
 878                         if (self::$driver == 'pdo') {
 879                                 self::e("SET autocommit=1");
 880                         } else {
 881                                 self::$db->autocommit(true);
 882                         }
 883                 } else {
 884                         self::$in_transaction = true;
 885                 }
 886                 return $success;
 887         }
 888
 889         /**
 890          * @brief Unlocks all locked tables
 891          *
 892          * @return boolean was the unlock successful?
 893          */
 894         public static function unlock() {
 895                 // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
 896                 self::performCommit();
 897
 898                 if (self::$driver == 'pdo') {
 899                         self::$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
 900                 }
 901
 902                 $success = self::e("UNLOCK TABLES");
 903
 904                 if (self::$driver == 'pdo') {
 905                         self::$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
 906                         self::e("SET autocommit=1");
 907                 } else {
 908                         self::$db->autocommit(true);
 909                 }
 910
 911                 self::$in_transaction = false;
 912                 return $success;
 913         }
 914
 915         /**
 916          * @brief Starts a transaction
 917          *
 918          * @return boolean Was the command executed successfully?
 919          */
 920         public static function transaction() {
 921                 if (!self::performCommit()) {
 922                         return false;
 923                 }
 924
 925                 switch (self::$driver) {
 926                         case 'pdo':
 927                                 if (self::$db->inTransaction()) {
 928                                         break;
 929                                 }
 930                                 if (!self::$db->beginTransaction()) {
 931                                         return false;
 932                                 }
 933                                 break;
 934                         case 'mysqli':
 935                                 if (!self::$db->begin_transaction()) {
 936                                         return false;
 937                                 }
 938                                 break;
 939                 }
 940
 941                 self::$in_transaction = true;
 942                 return true;
 943         }
 944
 945         private static function performCommit()
 946         {
 947                 switch (self::$driver) {
 948                         case 'pdo':
 949                                 if (!self::$db->inTransaction()) {
 950                                         return true;
 951                                 }
 952                                 return self::$db->commit();
 953                         case 'mysqli':
 954                                 return self::$db->commit();
 955                 }
 956                 return true;
 957         }
 958
 959         /**
 960          * @brief Does a commit
 961          *
 962          * @return boolean Was the command executed successfully?
 963          */
 964         public static function commit() {
 965                 if (!self::performCommit()) {
 966                         return false;
 967                 }
 968                 self::$in_transaction = false;
 969                 return true;
 970         }
 971
 972         /**
 973          * @brief Does a rollback
 974          *
 975          * @return boolean Was the command executed successfully?
 976          */
 977         public static function rollback() {
 978                 $ret = false;
 979
 980                 switch (self::$driver) {
 981                         case 'pdo':
 982                                 if (!self::$db->inTransaction()) {
 983                                         $ret = true;
 984                                         break;
 985                                 }
 986                                 $ret = self::$db->rollBack();
 987                                 break;
 988                         case 'mysqli':
 989                                 $ret = self::$db->rollback();
 990                                 break;
 991                 }
 992                 self::$in_transaction = false;
 993                 return $ret;
 994         }
 995
 996         /**
 997          * @brief Build the array with the table relations
 998          *
 999          * The array is build from the database definitions in DBStructure.php
1000          *
1001          * This process must only be started once, since the value is cached.
1002          */
1003         private static function buildRelationData() {
1004                 $definition = DBStructure::definition();
1005
1006                 foreach ($definition AS $table => $structure) {
1007                         foreach ($structure['fields'] AS $field => $field_struct) {
1008                                 if (isset($field_struct['relation'])) {
1009                                         foreach ($field_struct['relation'] AS $rel_table => $rel_field) {
1010                                                 self::$relation[$rel_table][$rel_field][$table][] = $field;
1011                                         }
1012                                 }
1013                         }
1014                 }
1015         }
1016
1017         /**
1018          * @brief Delete a row from a table
1019          *
1020          * @param string  $table       Table name
1021          * @param array   $conditions  Field condition(s)
1022          * @param array   $options
1023          *                - cascade: If true we delete records in other tables that depend on the one we're deleting through
1024          *                           relations (default: true)
1025          * @param boolean $in_process  Internal use: Only do a commit after the last delete
1026          * @param array   $callstack   Internal use: prevent endless loops
1027          *
1028          * @return boolean|array was the delete successful? When $in_process is set: deletion data
1029          */
1030         public static function delete($table, array $conditions, array $options = [], $in_process = false, array &$callstack = [])
1031         {
1032                 if (empty($table) || empty($conditions)) {
1033                         logger('Table and conditions have to be set');
1034                         return false;
1035                 }
1036
1037                 $commands = [];
1038
1039                 // Create a key for the loop prevention
1040                 $key = $table . ':' . json_encode($conditions);
1041
1042                 // We quit when this key already exists in the callstack.
1043                 if (isset($callstack[$key])) {
1044                         return $commands;
1045                 }
1046
1047                 $callstack[$key] = true;
1048
1049                 $table = self::escape($table);
1050
1051                 $commands[$key] = ['table' => $table, 'conditions' => $conditions];
1052
1053                 $cascade = defaults($options, 'cascade', true);
1054
1055                 // To speed up the whole process we cache the table relations
1056                 if ($cascade && count(self::$relation) == 0) {
1057                         self::buildRelationData();
1058                 }
1059
1060                 // Is there a relation entry for the table?
1061                 if ($cascade && isset(self::$relation[$table])) {
1062                         // We only allow a simple "one field" relation.
1063                         $field = array_keys(self::$relation[$table])[0];
1064                         $rel_def = array_values(self::$relation[$table])[0];
1065
1066                         // Create a key for preventing double queries
1067                         $qkey = $field . '-' . $table . ':' . json_encode($conditions);
1068
1069                         // When the search field is the relation field, we don't need to fetch the rows
1070                         // This is useful when the leading record is already deleted in the frontend but the rest is done in the backend
1071                         if ((count($conditions) == 1) && ($field == array_keys($conditions)[0])) {
1072                                 foreach ($rel_def AS $rel_table => $rel_fields) {
1073                                         foreach ($rel_fields AS $rel_field) {
1074                                                 $retval = self::delete($rel_table, [$rel_field => array_values($conditions)[0]], $options, true, $callstack);
1075                                                 $commands = array_merge($commands, $retval);
1076                                         }
1077                                 }
1078                                 // We quit when this key already exists in the callstack.
1079                         } elseif (!isset($callstack[$qkey])) {
1080
1081                                 $callstack[$qkey] = true;
1082
1083                                 // Fetch all rows that are to be deleted
1084                                 $data = self::select($table, [$field], $conditions);
1085
1086                                 while ($row = self::fetch($data)) {
1087                                         // Now we accumulate the delete commands
1088                                         $retval = self::delete($table, [$field => $row[$field]], $options, true, $callstack);
1089                                         $commands = array_merge($commands, $retval);
1090                                 }
1091
1092                                 self::close($data);
1093
1094                                 // Since we had split the delete command we don't need the original command anymore
1095                                 unset($commands[$key]);
1096                         }
1097                 }
1098
1099                 if (!$in_process) {
1100                         // Now we finalize the process
1101                         $do_transaction = !self::$in_transaction;
1102
1103                         if ($do_transaction) {
1104                                 self::transaction();
1105                         }
1106
1107                         $compacted = [];
1108                         $counter = [];
1109
1110                         foreach ($commands AS $command) {
1111                                 $conditions = $command['conditions'];
1112                                 reset($conditions);
1113                                 $first_key = key($conditions);
1114
1115                                 $condition_string = self::buildCondition($conditions);
1116
1117                                 if ((count($command['conditions']) > 1) || is_int($first_key)) {
1118                                         $sql = "DELETE FROM `" . $command['table'] . "`" . $condition_string;
1119                                         logger(self::replaceParameters($sql, $conditions), LOGGER_DATA);
1120
1121                                         if (!self::e($sql, $conditions)) {
1122                                                 if ($do_transaction) {
1123                                                         self::rollback();
1124                                                 }
1125                                                 return false;
1126                                         }
1127                                 } else {
1128                                         $key_table = $command['table'];
1129                                         $key_condition = array_keys($command['conditions'])[0];
1130                                         $value = array_values($command['conditions'])[0];
1131
1132                                         // Split the SQL queries in chunks of 100 values
1133                                         // We do the $i stuff here to make the code better readable
1134                                         $i = isset($counter[$key_table][$key_condition]) ? $counter[$key_table][$key_condition] : 0;
1135                                         if (isset($compacted[$key_table][$key_condition][$i]) && count($compacted[$key_table][$key_condition][$i]) > 100) {
1136                                                 ++$i;
1137                                         }
1138
1139                                         $compacted[$key_table][$key_condition][$i][$value] = $value;
1140                                         $counter[$key_table][$key_condition] = $i;
1141                                 }
1142                         }
1143                         foreach ($compacted AS $table => $values) {
1144                                 foreach ($values AS $field => $field_value_list) {
1145                                         foreach ($field_value_list AS $field_values) {
1146                                                 $sql = "DELETE FROM `" . $table . "` WHERE `" . $field . "` IN (" .
1147                                                         substr(str_repeat("?, ", count($field_values)), 0, -2) . ");";
1148
1149                                                 logger(self::replaceParameters($sql, $field_values), LOGGER_DATA);
1150
1151                                                 if (!self::e($sql, $field_values)) {
1152                                                         if ($do_transaction) {
1153                                                                 self::rollback();
1154                                                         }
1155                                                         return false;
1156                                                 }
1157                                         }
1158                                 }
1159                         }
1160                         if ($do_transaction) {
1161                                 self::commit();
1162                         }
1163                         return true;
1164                 }
1165
1166                 return $commands;
1167         }
1168
1169         /**
1170          * @brief Updates rows
1171          *
1172          * Updates rows in the database. When $old_fields is set to an array,
1173          * the system will only do an update if the fields in that array changed.
1174          *
1175          * Attention:
1176          * Only the values in $old_fields are compared.
1177          * This is an intentional behaviour.
1178          *
1179          * Example:
1180          * We include the timestamp field in $fields but not in $old_fields.
1181          * Then the row will only get the new timestamp when the other fields had changed.
1182          *
1183          * When $old_fields is set to a boolean value the system will do this compare itself.
1184          * When $old_fields is set to "true" the system will do an insert if the row doesn't exists.
1185          *
1186          * Attention:
1187          * Only set $old_fields to a boolean value when you are sure that you will update a single row.
1188          * When you set $old_fields to "true" then $fields must contain all relevant fields!
1189          *
1190          * @param string $table Table name
1191          * @param array $fields contains the fields that are updated
1192          * @param array $condition condition array with the key values
1193          * @param array|boolean $old_fields array with the old field values that are about to be replaced (true = update on duplicate)
1194          *
1195          * @return boolean was the update successfull?
1196          */
1197         public static function update($table, $fields, $condition, $old_fields = []) {
1198
1199                 if (empty($table) || empty($fields) || empty($condition)) {
1200                         logger('Table, fields and condition have to be set');
1201                         return false;
1202                 }
1203
1204                 $table = self::escape($table);
1205
1206                 $condition_string = self::buildCondition($condition);
1207
1208                 if (is_bool($old_fields)) {
1209                         $do_insert = $old_fields;
1210
1211                         $old_fields = self::selectFirst($table, [], $condition);
1212
1213                         if (is_bool($old_fields)) {
1214                                 if ($do_insert) {
1215                                         $values = array_merge($condition, $fields);
1216                                         return self::insert($table, $values, $do_insert);
1217                                 }
1218                                 $old_fields = [];
1219                         }
1220                 }
1221
1222                 $do_update = (count($old_fields) == 0);
1223
1224                 foreach ($old_fields AS $fieldname => $content) {
1225                         if (isset($fields[$fieldname])) {
1226                                 if ($fields[$fieldname] == $content) {
1227                                         unset($fields[$fieldname]);
1228                                 } else {
1229                                         $do_update = true;
1230                                 }
1231                         }
1232                 }
1233
1234                 if (!$do_update || (count($fields) == 0)) {
1235                         return true;
1236                 }
1237
1238                 $sql = "UPDATE `".$table."` SET `".
1239                         implode("` = ?, `", array_keys($fields))."` = ?".$condition_string;
1240
1241                 $params1 = array_values($fields);
1242                 $params2 = array_values($condition);
1243                 $params = array_merge_recursive($params1, $params2);
1244
1245                 return self::e($sql, $params);
1246         }
1247
1248         /**
1249          * Retrieve a single record from a table and returns it in an associative array
1250          *
1251          * @brief Retrieve a single record from a table
1252          * @param string $table
1253          * @param array  $fields
1254          * @param array  $condition
1255          * @param array  $params
1256          * @return bool|array
1257          * @see self::select
1258          */
1259         public static function selectFirst($table, array $fields = [], array $condition = [], $params = [])
1260         {
1261                 $params['limit'] = 1;
1262                 $result = self::select($table, $fields, $condition, $params);
1263
1264                 if (is_bool($result)) {
1265                         return $result;
1266                 } else {
1267                         $row = self::fetch($result);
1268                         self::close($result);
1269                         return $row;
1270                 }
1271         }
1272
1273         /**
1274          * @brief Select rows from a table
1275          *
1276          * @param string $table     Table name
1277          * @param array  $fields    Array of selected fields, empty for all
1278          * @param array  $condition Array of fields for condition
1279          * @param array  $params    Array of several parameters
1280          *
1281          * @return boolean|object
1282          *
1283          * Example:
1284          * $table = "item";
1285          * $fields = array("id", "uri", "uid", "network");
1286          *
1287          * $condition = array("uid" => 1, "network" => 'dspr');
1288          * or:
1289          * $condition = array("`uid` = ? AND `network` IN (?, ?)", 1, 'dfrn', 'dspr');
1290          *
1291          * $params = array("order" => array("id", "received" => true), "limit" => 10);
1292          *
1293          * $data = dba::select($table, $fields, $condition, $params);
1294          */
1295         public static function select($table, array $fields = [], array $condition = [], array $params = [])
1296         {
1297                 if ($table == '') {
1298                         return false;
1299                 }
1300
1301                 $table = self::escape($table);
1302
1303                 if (count($fields) > 0) {
1304                         $select_fields = "`" . implode("`, `", array_values($fields)) . "`";
1305                 } else {
1306                         $select_fields = "*";
1307                 }
1308
1309                 $condition_string = self::buildCondition($condition);
1310
1311                 $param_string = self::buildParameter($params);
1312
1313                 $sql = "SELECT " . $select_fields . " FROM `" . $table . "`" . $condition_string . $param_string;
1314
1315                 $result = self::p($sql, $condition);
1316
1317                 return $result;
1318         }
1319
1320         /**
1321          * @brief Counts the rows from a table satisfying the provided condition
1322          *
1323          * @param string $table Table name
1324          * @param array $condition array of fields for condition
1325          *
1326          * @return int
1327          *
1328          * Example:
1329          * $table = "item";
1330          *
1331          * $condition = ["uid" => 1, "network" => 'dspr'];
1332          * or:
1333          * $condition = ["`uid` = ? AND `network` IN (?, ?)", 1, 'dfrn', 'dspr'];
1334          *
1335          * $count = dba::count($table, $condition);
1336          */
1337         public static function count($table, array $condition = [])
1338         {
1339                 if ($table == '') {
1340                         return false;
1341                 }
1342
1343                 $condition_string = self::buildCondition($condition);
1344
1345                 $sql = "SELECT COUNT(*) AS `count` FROM `".$table."`".$condition_string;
1346
1347                 $row = self::fetch_first($sql, $condition);
1348
1349                 return $row['count'];
1350         }
1351
1352         /**
1353          * @brief Returns the SQL condition string built from the provided condition array
1354          *
1355          * This function operates with two modes.
1356          * - Supplied with a filed/value associative array, it builds simple strict
1357          *   equality conditions linked by AND.
1358          * - Supplied with a flat list, the first element is the condition string and
1359          *   the following arguments are the values to be interpolated
1360          *
1361          * $condition = ["uid" => 1, "network" => 'dspr'];
1362          * or:
1363          * $condition = ["`uid` = ? AND `network` IN (?, ?)", 1, 'dfrn', 'dspr'];
1364          *
1365          * In either case, the provided array is left with the parameters only
1366          *
1367          * @param array $condition
1368          * @return string
1369          */
1370         public static function buildCondition(array &$condition = [])
1371         {
1372                 $condition_string = '';
1373                 if (count($condition) > 0) {
1374                         reset($condition);
1375                         $first_key = key($condition);
1376                         if (is_int($first_key)) {
1377                                 $condition_string = " WHERE (" . array_shift($condition) . ")";
1378                         } else {
1379                                 $new_values = [];
1380                                 $condition_string = "";
1381                                 foreach ($condition as $field => $value) {
1382                                         if ($condition_string != "") {
1383                                                 $condition_string .= " AND ";
1384                                         }
1385                                         if (is_array($value)) {
1386                                                 /* Workaround for MySQL Bug #64791.
1387                                                  * Never mix data types inside any IN() condition.
1388                                                  * In case of mixed types, cast all as string.
1389                                                  * Logic needs to be consistent with dba::p() data types.
1390                                                  */
1391                                                 $is_int = false;
1392                                                 $is_alpha = false;
1393                                                 foreach ($value as $single_value) {
1394                                                         if (is_int($single_value)) {
1395                                                                 $is_int = true;
1396                                                         } else {
1397                                                                 $is_alpha = true;
1398                                                         }
1399                                                 }
1400
1401                                                 if ($is_int && $is_alpha) {
1402                                                         foreach ($value as &$ref) {
1403                                                                 if (is_int($ref)) {
1404                                                                         $ref = (string)$ref;
1405                                                                 }
1406                                                         }
1407                                                         unset($ref); //Prevent accidental re-use.
1408                                                 }
1409
1410                                                 $new_values = array_merge($new_values, array_values($value));
1411                                                 $placeholders = substr(str_repeat("?, ", count($value)), 0, -2);
1412                                                 $condition_string .= "`" . $field . "` IN (" . $placeholders . ")";
1413                                         } else {
1414                                                 $new_values[$field] = $value;
1415                                                 $condition_string .= "`" . $field . "` = ?";
1416                                         }
1417                                 }
1418                                 $condition_string = " WHERE (" . $condition_string . ")";
1419                                 $condition = $new_values;
1420                         }
1421                 }
1422
1423                 return $condition_string;
1424         }
1425
1426         /**
1427          * @brief Returns the SQL parameter string built from the provided parameter array
1428          *
1429          * @param array $params
1430          * @return string
1431          */
1432         public static function buildParameter(array $params = [])
1433         {
1434                 $order_string = '';
1435                 if (isset($params['order'])) {
1436                         $order_string = " ORDER BY ";
1437                         foreach ($params['order'] AS $fields => $order) {
1438                                 if (!is_int($fields)) {
1439                                         $order_string .= "`" . $fields . "` " . ($order ? "DESC" : "ASC") . ", ";
1440                                 } else {
1441                                         $order_string .= "`" . $order . "`, ";
1442                                 }
1443                         }
1444                         $order_string = substr($order_string, 0, -2);
1445                 }
1446
1447                 $limit_string = '';
1448                 if (isset($params['limit']) && is_int($params['limit'])) {
1449                         $limit_string = " LIMIT " . $params['limit'];
1450                 }
1451
1452                 if (isset($params['limit']) && is_array($params['limit'])) {
1453                         $limit_string = " LIMIT " . intval($params['limit'][0]) . ", " . intval($params['limit'][1]);
1454                 }
1455
1456                 return $order_string.$limit_string;
1457         }
1458
1459         /**
1460          * @brief Fills an array with data from a query
1461          *
1462          * @param object $stmt statement object
1463          * @return array Data array
1464          */
1465         public static function inArray($stmt, $do_close = true) {
1466                 if (is_bool($stmt)) {
1467                         return $stmt;
1468                 }
1469
1470                 $data = [];
1471                 while ($row = self::fetch($stmt)) {
1472                         $data[] = $row;
1473                 }
1474                 if ($do_close) {
1475                         self::close($stmt);
1476                 }
1477                 return $data;
1478         }
1479
1480         /**
1481          * @brief Returns the error number of the last query
1482          *
1483          * @return string Error number (0 if no error)
1484          */
1485         public static function errorNo() {
1486                 return self::$errorno;
1487         }
1488
1489         /**
1490          * @brief Returns the error message of the last query
1491          *
1492          * @return string Error message ('' if no error)
1493          */
1494         public static function errorMessage() {
1495                 return self::$error;
1496         }
1497
1498         /**
1499          * @brief Closes the current statement
1500          *
1501          * @param object $stmt statement object
1502          * @return boolean was the close successful?
1503          */
1504         public static function close($stmt) {
1505                 $a = get_app();
1506
1507                 $stamp1 = microtime(true);
1508
1509                 if (!is_object($stmt)) {
1510                         return false;
1511                 }
1512
1513                 switch (self::$driver) {
1514                         case 'pdo':
1515                                 $ret = $stmt->closeCursor();
1516                                 break;
1517                         case 'mysqli':
1518                                 // MySQLi offers both a mysqli_stmt and a mysqli_result class.
1519                                 // We should be careful not to assume the object type of $stmt
1520                                 // because dba::p() has been able to return both types.
1521                                 if ($stmt instanceof mysqli_stmt) {
1522                                         $stmt->free_result();
1523                                         $ret = $stmt->close();
1524                                 } elseif ($stmt instanceof mysqli_result) {
1525                                         $stmt->free();
1526                                         $ret = true;
1527                                 } else {
1528                                         $ret = false;
1529                                 }
1530                                 break;
1531                 }
1532
1533                 $a->save_timestamp($stamp1, 'database');
1534
1535                 return $ret;
1536         }
1537 }