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