<?php

// $Id: database.mysql.inc,v 1.89 2008/01/24 10:46:54 goba Exp $

/**

 * @file

 * Database interface code for MySQL database servers.

 */

/**

 * @ingroup database

 * @{

 */

// Include functions shared between mysql and mysqli.

require_once './includes/database.mysql-common.inc';

/**

 * Report database status.

 */

function db_status_report($phase) {

  $t = get_t();

  $version = db_version();

  $form['mysql'] = array(

    'title' => $t('MySQL database'),

    'value' => ($phase == 'runtime') ? l($version, 'admin/reports/status/sql') : $version,

  );

  if (version_compare($version, DRUPAL_MINIMUM_MYSQL) < 0) {

    $form['mysql']['severity'] = REQUIREMENT_ERROR;

    $form['mysql']['description'] = $t('Your MySQL Server is too old. Drupal requires at least MySQL %version.', array('%version' => DRUPAL_MINIMUM_MYSQL));

  }

  return $form;

}

/**

 * Returns the version of the database server currently in use.

 *

 * @return Database server version

 */

function db_version() {

  list($version) = explode('-', mysql_get_server_info());

  return $version;

}

/**

 * Initialize a database connection.

 */

function db_connect($url) {

  $url = parse_url($url);

  // Check if MySQL support is present in PHP

  if (!function_exists('mysql_connect')) {

    _db_error_page('Unable to use the MySQL database because the MySQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');

  }

  // Decode url-encoded information in the db connection string

  $url['user'] = urldecode($url['user']);

  // Test if database url has a password.

  $url['pass'] = isset($url['pass']) ? urldecode($url['pass']) : '';

  $url['host'] = urldecode($url['host']);

  $url['path'] = urldecode($url['path']);

  // Allow for non-standard MySQL port.

  if (isset($url['port'])) {

    $url['host'] = $url['host'] .':'. $url['port'];

  }

  // - TRUE makes mysql_connect() always open a new link, even if

  //   mysql_connect() was called before with the same parameters.

  //   This is important if you are using two databases on the same

  //   server.

  // - 2 means CLIENT_FOUND_ROWS: return the number of found

  //   (matched) rows, not the number of affected rows.

  $connection = @mysql_connect($url['host'], $url['user'], $url['pass'], TRUE, 2);

  if (!$connection || !mysql_select_db(substr($url['path'], 1))) {

    // Show error screen otherwise

    _db_error_page(mysql_error());

  }

  // Force UTF-8.

  mysql_query('SET NAMES "utf8"', $connection);

  return $connection;

}

/**

 * Helper function for db_query().

 */

function _db_query($query, $debug = 0) {

  global $active_db, $queries, $user;

  if (variable_get('dev_query', 0)) {

    list($usec, $sec) = explode(' ', microtime());

    $timer = (float)$usec + (float)$sec;

    // If devel.module query logging is enabled, prepend a comment with the username and calling function

    // to the SQL string. This is useful when running mysql's SHOW PROCESSLIST to learn what exact

    // code is issueing the slow query.

    $bt = debug_backtrace();

    // t() may not be available yet so we don't wrap 'Anonymous'.

    $name = $user->uid ? $user->name : variable_get('anonymous', 'Anonymous');

    // str_replace() to prevent SQL injection via username or anonymous name.

    $name = str_replace(array('*', '/'), '', $name);

    $query = '/* '. $name .' : '. $bt[2]['function'] .' */ '. $query;

  }

  $result = mysql_query($query, $active_db);

  if (variable_get('dev_query', 0)) {

    $query = $bt[2]['function'] ."\n". $query;

    list($usec, $sec) = explode(' ', microtime());

    $stop = (float)$usec + (float)$sec;

    $diff = $stop - $timer;

    $queries[] = array($query, $diff);

  }

  if ($debug) {

    print '<p>query: '. $query .'<br />error:'. mysql_error($active_db) .'</p>';

  }

  if (!mysql_errno($active_db)) {

    return $result;

  }

  else {

    // Indicate to drupal_error_handler that this is a database error.

    ${DB_ERROR} = TRUE;

    trigger_error(check_plain(mysql_error($active_db) ."\nquery: ". $query), E_USER_WARNING);

    return FALSE;

  }

}

/**

 * Fetch one result row from the previous query as an object.

 *

 * @param $result

 *   A database query result resource, as returned from db_query().

 * @return

 *   An object representing the next row of the result, or FALSE. The attributes

 *   of this object are the table fields selected by the query.

 */

function db_fetch_object($result) {

  if ($result) {

    return mysql_fetch_object($result);

  }

}

/**

 * Fetch one result row from the previous query as an array.

 *

 * @param $result

 *   A database query result resource, as returned from db_query().

 * @return

 *   An associative array representing the next row of the result, or FALSE.

 *   The keys of this object are the names of the table fields selected by the

 *   query, and the values are the field values for this result row.

 */

function db_fetch_array($result) {

  if ($result) {

    return mysql_fetch_array($result, MYSQL_ASSOC);

  }

}

/**

 * Return an individual result field from the previous query.

 *

 * Only use this function if exactly one field is being selected; otherwise,

 * use db_fetch_object() or db_fetch_array().

 *

 * @param $result

 *   A database query result resource, as returned from db_query().

 * @return

 *   The resulting field or FALSE.

 */

function db_result($result) {

  if ($result && mysql_num_rows($result) > 0) {

    // The mysql_fetch_row function has an optional second parameter $row

    // but that can't be used for compatibility with Oracle, DB2, etc.

    $array = mysql_fetch_row($result);

    return $array[0];

  }

  return FALSE;

}

/**

 * Determine whether the previous query caused an error.

 */

function db_error() {

  global $active_db;

  return mysql_errno($active_db);

}

/**

 * Determine the number of rows changed by the preceding query.

 */

function db_affected_rows() {

  global $active_db;

  return mysql_affected_rows($active_db);

}

/**

 * Runs a limited-range query in the active database.

 *

 * Use this as a substitute for db_query() when a subset of the query is to be

 * returned.

 * User-supplied arguments to the query should be passed in as separate parameters

 * so that they can be properly escaped to avoid SQL injection attacks.

 *

 * @param $query

 *   A string containing an SQL query.

 * @param ...

 *   A variable number of arguments which are substituted into the query

 *   using printf() syntax. The query arguments can be enclosed in one

 *   array instead.

 *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose

 *   in '') and %%.

 *

 *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,

 *   and TRUE values to decimal 1.

 *

 * @param $from

 *   The first result row to return.

 * @param $count

 *   The maximum number of result rows to return.

 * @return

 *   A database query result resource, or FALSE if the query was not executed

 *   correctly.

 */

function db_query_range($query) {

  $args = func_get_args();

  $count = array_pop($args);

  $from = array_pop($args);

  array_shift($args);

  $query = db_prefix_tables($query);

  if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax

    $args = $args[0];

  }

  _db_query_callback($args, TRUE);

  $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);

  $query .= ' LIMIT '. (int)$from .', '. (int)$count;

  return _db_query($query);

}

/**

 * Runs a SELECT query and stores its results in a temporary table.

 *

 * Use this as a substitute for db_query() when the results need to stored

 * in a temporary table. Temporary tables exist for the duration of the page

 * request.

 * User-supplied arguments to the query should be passed in as separate parameters

 * so that they can be properly escaped to avoid SQL injection attacks.

 *

 * Note that if you need to know how many results were returned, you should do

 * a SELECT COUNT(*) on the temporary table afterwards. db_affected_rows() does

 * not give consistent result across different database types in this case.

 *

 * @param $query

 *   A string containing a normal SELECT SQL query.

 * @param ...

 *   A variable number of arguments which are substituted into the query

 *   using printf() syntax. The query arguments can be enclosed in one

 *   array instead.

 *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose

 *   in '') and %%.

 *

 *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,

 *   and TRUE values to decimal 1.

 *

 * @param $table

 *   The name of the temporary table to select into. This name will not be

 *   prefixed as there is no risk of collision.

 * @return

 *   A database query result resource, or FALSE if the query was not executed

 *   correctly.

 */

function db_query_temporary($query) {

  $args = func_get_args();

  $tablename = array_pop($args);

  array_shift($args);

  $query = preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE '. $tablename .' Engine=HEAP SELECT', db_prefix_tables($query));

  if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax

    $args = $args[0];

  }

  _db_query_callback($args, TRUE);

  $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);

  return _db_query($query);

}

/**

 * Returns a properly formatted Binary Large OBject value.

 *

 * @param $data

 *   Data to encode.

 * @return

 *  Encoded data.

 */

function db_encode_blob($data) {

  global $active_db;

  return "'". mysql_real_escape_string($data, $active_db) ."'";

}

/**

 * Returns text from a Binary Large Object value.

 *

 * @param $data

 *   Data to decode.

 * @return

 *  Decoded data.

 */

function db_decode_blob($data) {

  return $data;

}

/**

 * Prepare user input for use in a database query, preventing SQL injection attacks.

 */

function db_escape_string($text) {

  global $active_db;

  return mysql_real_escape_string($text, $active_db);

}

/**

 * Lock a table.

 */

function db_lock_table($table) {

  db_query('LOCK TABLES {'. db_escape_table($table) .'} WRITE');

}

/**

 * Unlock all locked tables.

 */

function db_unlock_tables() {

  db_query('UNLOCK TABLES');

}

/**

 * Check if a table exists.

 */

function db_table_exists($table) {

  return (bool) db_fetch_object(db_query("SHOW TABLES LIKE '{". db_escape_table($table) ."}'"));

}

/**

 * Check if a column exists in the given table.

 */

function db_column_exists($table, $column) {

  return (bool) db_fetch_object(db_query("SHOW COLUMNS FROM {". db_escape_table($table) ."} LIKE '". db_escape_table($column) ."'"));

}

/**

 * Wraps the given table.field entry with a DISTINCT(). The wrapper is added to

 * the SELECT list entry of the given query and the resulting query is returned.

 * This function only applies the wrapper if a DISTINCT doesn't already exist in

 * the query.

 *

 * @param $table Table containing the field to set as DISTINCT

 * @param $field Field to set as DISTINCT

 * @param $query Query to apply the wrapper to

 * @return SQL query with the DISTINCT wrapper surrounding the given table.field.

 */

function db_distinct_field($table, $field, $query) {

  $field_to_select = 'DISTINCT('. $table .'.'. $field .')';

  // (?<!text) is a negative look-behind (no need to rewrite queries that already use DISTINCT).

  return preg_replace('/(SELECT.*)(?:'. $table .'\.|\s)(?<!DISTINCT\()(?<!DISTINCT\('. $table .'\.)'. $field .'(.*FROM )/AUsi', '\1 '. $field_to_select .'\2', $query);

}

/**

 * @} End of "ingroup database".

 */