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<?php

/**
 * This file contains database functionality specifically designed for packages (mods) to utilize.
 *
 * Simple Machines Forum (SMF)
 *
 * @package SMF
 * @author Simple Machines https://www.simplemachines.org
 * @copyright 2020 Simple Machines and individual contributors
 * @license https://www.simplemachines.org/about/smf/license.php BSD
 *
 * @version 2.1 RC2
 */

if (!defined('SMF'))
    die('No direct access...');

/**
 * Add the file functions to the $smcFunc array.
 */
function db_packages_init()
{
    global $smcFunc, $reservedTables, $db_package_log, $db_prefix;

    if (!isset($smcFunc['db_create_table']) || $smcFunc['db_create_table'] != 'smf_db_create_table')
    {
        $smcFunc += array(
            'db_add_column' => 'smf_db_add_column',
            'db_add_index' => 'smf_db_add_index',
            'db_calculate_type' => 'smf_db_calculate_type',
            'db_change_column' => 'smf_db_change_column',
            'db_create_table' => 'smf_db_create_table',
            'db_drop_table' => 'smf_db_drop_table',
            'db_table_structure' => 'smf_db_table_structure',
            'db_list_columns' => 'smf_db_list_columns',
            'db_list_indexes' => 'smf_db_list_indexes',
            'db_remove_column' => 'smf_db_remove_column',
            'db_remove_index' => 'smf_db_remove_index',
        );
        $db_package_log = array();
    }

    // We setup an array of SMF tables we can't do auto-remove on - in case a mod writer cocks it up!
    $reservedTables = array(
        'admin_info_files', 'approval_queue', 'attachments',
        'background_tasks', 'ban_groups', 'ban_items', 'board_permissions',
        'board_permissions_view', 'boards', 'calendar', 'calendar_holidays',
        'categories', 'custom_fields', 'group_moderators', 'log_actions',
        'log_activity', 'log_banned', 'log_boards', 'log_comments',
        'log_digest', 'log_errors', 'log_floodcontrol', 'log_group_requests',
        'log_mark_read', 'log_member_notices', 'log_notify', 'log_online',
        'log_packages', 'log_polls', 'log_reported', 'log_reported_comments',
        'log_scheduled_tasks', 'log_search_messages', 'log_search_results',
        'log_search_subjects', 'log_search_topics', 'log_spider_hits',
        'log_spider_stats', 'log_subscribed', 'log_topics', 'mail_queue',
        'member_logins', 'membergroups', 'members', 'mentions',
        'message_icons', 'messages', 'moderator_groups', 'moderators',
        'package_servers', 'permission_profiles', 'permissions',
        'personal_messages', 'pm_labeled_messages', 'pm_labels',
        'pm_recipients', 'pm_rules', 'poll_choices', 'polls', 'qanda',
        'scheduled_tasks', 'sessions', 'settings', 'smiley_files', 'smileys',
        'spiders', 'subscriptions', 'themes', 'topics', 'user_alerts',
        'user_alerts_prefs', 'user_drafts', 'user_likes',
    );
    foreach ($reservedTables as $k => $table_name)
        $reservedTables[$k] = strtolower($db_prefix . $table_name);

    // We in turn may need the extra stuff.
    db_extend('extra');
}

/**
 * This function can be used to create a table without worrying about schema
 *  compatibilities across supported database systems.
 *  - If the table exists will, by default, do nothing.
 *  - Builds table with columns as passed to it - at least one column must be sent.
 *  The columns array should have one sub-array for each column - these sub arrays contain:
 *      'name' = Column name
 *      'type' = Type of column - values from (smallint, mediumint, int, text, varchar, char, tinytext, mediumtext, largetext)
 *      'size' => Size of column (If applicable) - for example 255 for a large varchar, 10 for an int etc.
 *          If not set SMF will pick a size.
 *      - 'default' = Default value - do not set if no default required.
 *      - 'null' => Can it be null (true or false) - if not set default will be false.
 *      - 'auto' => Set to true to make it an auto incrementing column. Set to a numerical value to set from what
 *           it should begin counting.
 *  - Adds indexes as specified within indexes parameter. Each index should be a member of $indexes. Values are:
 *      - 'name' => Index name (If left empty SMF will generate).
 *      - 'type' => Type of index. Choose from 'primary', 'unique' or 'index'. If not set will default to 'index'.
 *      - 'columns' => Array containing columns that form part of key - in the order the index is to be created.
 *  - parameters: (None yet)
 *  - if_exists values:
 *      - 'ignore' will do nothing if the table exists. (And will return true)
 *      - 'overwrite' will drop any existing table of the same name.
 *      - 'error' will return false if the table already exists.
 *      - 'update' will update the table if the table already exists (no change of ai field and only colums with the same name keep the data)
 *
 * @param string $table_name The name of the table to create
 * @param array $columns An array of column info in the specified format
 * @param array $indexes An array of index info in the specified format
 * @param array $parameters Extra parameters. Currently only 'engine', the desired MySQL storage engine, is used.
 * @param string $if_exists What to do if the table exists.
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_create_table($table_name, $columns, $indexes = array(), $parameters = array(), $if_exists = 'ignore', $error = 'fatal')
{
    global $reservedTables, $smcFunc, $db_package_log, $db_prefix, $db_character_set, $db_name;

    static $engines = array();

    $old_table_exists = false;

    // Strip out the table name, we might not need it in some cases
    $real_prefix = preg_match('~^(`?)(.+?)\\1\\.(.*?)$~', $db_prefix, $match) === 1 ? $match[3] : $db_prefix;

    // With or without the database name, the fullname looks like this.
    $full_table_name = str_replace('{db_prefix}', $real_prefix, $table_name);
    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // First - no way do we touch SMF tables.
    if (in_array(strtolower($table_name), $reservedTables))
        return false;

    // Log that we'll want to remove this on uninstall.
    $db_package_log[] = array('remove_table', $table_name);

    // Slightly easier on MySQL than the others...
    $tables = $smcFunc['db_list_tables']();
    if (in_array($full_table_name, $tables))
    {
        // This is a sad day... drop the table? If not, return false (error) by default.
        if ($if_exists == 'overwrite')
            $smcFunc['db_drop_table']($table_name);
        elseif ($if_exists == 'update')
        {
            $smcFunc['db_transaction']('begin');
            $db_trans = true;
            $smcFunc['db_drop_table']($table_name . '_old');
            $smcFunc['db_query']('', '
                RENAME TABLE ' . $table_name . ' TO ' . $table_name . '_old',
                array(
                    'security_override' => true,
                )
            );
            $old_table_exists = true;
        }
        else
            return $if_exists == 'ignore';
    }

    // Righty - let's do the damn thing!
    $table_query = 'CREATE TABLE ' . $table_name . "\n" . '(';
    foreach ($columns as $column)
        $table_query .= "\n\t" . smf_db_create_query_column($column) . ',';

    // Loop through the indexes next...
    foreach ($indexes as $index)
    {
        $columns = implode(',', $index['columns']);

        // Is it the primary?
        if (isset($index['type']) && $index['type'] == 'primary')
            $table_query .= "\n\t" . 'PRIMARY KEY (' . implode(',', $index['columns']) . '),';
        else
        {
            if (empty($index['name']))
                $index['name'] = implode('_', $index['columns']);
            $table_query .= "\n\t" . (isset($index['type']) && $index['type'] == 'unique' ? 'UNIQUE' : 'KEY') . ' ' . $index['name'] . ' (' . $columns . '),';
        }
    }

    // No trailing commas!
    if (substr($table_query, -1) == ',')
        $table_query = substr($table_query, 0, -1);

    // Which engine do we want here?
    if (empty($engines))
    {
        // Figure out which engines we have
        $get_engines = $smcFunc['db_query']('', 'SHOW ENGINES', array());

        while ($row = $smcFunc['db_fetch_assoc']($get_engines))
        {
            if ($row['Support'] == 'YES' || $row['Support'] == 'DEFAULT')
                $engines[] = $row['Engine'];
        }

        $smcFunc['db_free_result']($get_engines);
    }

    // If we don't have this engine, or didn't specify one, default to InnoDB or MyISAM
    // depending on which one is available
    if (!isset($parameters['engine']) || !in_array($parameters['engine'], $engines))
    {
        $parameters['engine'] = in_array('InnoDB', $engines) ? 'InnoDB' : 'MyISAM';
    }

    $table_query .= ') ENGINE=' . $parameters['engine'];
    if (!empty($db_character_set) && $db_character_set == 'utf8')
        $table_query .= ' DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci';

    // Create the table!
    $smcFunc['db_query']('', $table_query,
        array(
            'security_override' => true,
        )
    );

    // Fill the old data
    if ($old_table_exists)
    {
        $same_col = array();

        $request = $smcFunc['db_query']('', '
            SELECT count(*), column_name
            FROM information_schema.columns
            WHERE table_name in ({string:table1},{string:table2}) AND table_schema = {string:schema}
            GROUP BY column_name
            HAVING count(*) > 1',
            array(
                'table1' => $table_name,
                'table2' => $table_name . '_old',
                'schema' => $db_name,
            )
        );

        while ($row = $smcFunc['db_fetch_assoc']($request))
        {
            $same_col[] = $row['column_name'];
        }

        $smcFunc['db_query']('', '
            INSERT INTO ' . $table_name . '('
            . implode($same_col, ',') .
            ')
            SELECT ' . implode($same_col, ',') . '
            FROM ' . $table_name . '_old',
            array()
        );

        $smcFunc['db_drop_table']($table_name . '_old');
    }

    return true;
}

/**
 * Drop a table.
 *
 * @param string $table_name The name of the table to drop
 * @param array $parameters Not used at the moment
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_drop_table($table_name, $parameters = array(), $error = 'fatal')
{
    global $reservedTables, $smcFunc, $db_prefix;

    // After stripping away the database name, this is what's left.
    $real_prefix = preg_match('~^(`?)(.+?)\\1\\.(.*?)$~', $db_prefix, $match) === 1 ? $match[3] : $db_prefix;

    // Get some aliases.
    $full_table_name = str_replace('{db_prefix}', $real_prefix, $table_name);
    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // God no - dropping one of these = bad.
    if (in_array(strtolower($table_name), $reservedTables))
        return false;

    // Does it exist?
    if (in_array($full_table_name, $smcFunc['db_list_tables']()))
    {
        $query = 'DROP TABLE ' . $table_name;
        $smcFunc['db_query']('',
            $query,
            array(
                'security_override' => true,
            )
        );

        return true;
    }

    // Otherwise do 'nout.
    return false;
}

/**
 * This function adds a column.
 *
 * @param string $table_name The name of the table to add the column to
 * @param array $column_info An array of column info ({@see smf_db_create_table})
 * @param array $parameters Not used?
 * @param string $if_exists What to do if the column exists. If 'update', column is updated.
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_add_column($table_name, $column_info, $parameters = array(), $if_exists = 'update', $error = 'fatal')
{
    global $smcFunc, $db_package_log, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // Log that we will want to uninstall this!
    $db_package_log[] = array('remove_column', $table_name, $column_info['name']);

    // Does it exist - if so don't add it again!
    $columns = $smcFunc['db_list_columns']($table_name, false);
    foreach ($columns as $column)
        if ($column == $column_info['name'])
        {
            // If we're going to overwrite then use change column.
            if ($if_exists == 'update')
                return $smcFunc['db_change_column']($table_name, $column_info['name'], $column_info);
            else
                return false;
        }

    // Get the specifics...
    $column_info['size'] = isset($column_info['size']) && is_numeric($column_info['size']) ? $column_info['size'] : null;

    // Now add the thing!
    $query = '
        ALTER TABLE ' . $table_name . '
        ADD ' . smf_db_create_query_column($column_info) . (empty($column_info['auto']) ? '' : ' primary key'
    );
    $smcFunc['db_query']('', $query,
        array(
            'security_override' => true,
        )
    );

    return true;
}

/**
 * Removes a column.
 *
 * @param string $table_name The name of the table to drop the column from
 * @param string $column_name The name of the column to drop
 * @param array $parameters Not used?
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_remove_column($table_name, $column_name, $parameters = array(), $error = 'fatal')
{
    global $smcFunc, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // Does it exist?
    $columns = $smcFunc['db_list_columns']($table_name, true);
    foreach ($columns as $column)
        if ($column['name'] == $column_name)
        {
            $smcFunc['db_query']('', '
                ALTER TABLE ' . $table_name . '
                DROP COLUMN ' . $column_name,
                array(
                    'security_override' => true,
                )
            );

            return true;
        }

    // If here we didn't have to work - joy!
    return false;
}

/**
 * Change a column.
 *
 * @param string $table_name The name of the table this column is in
 * @param string $old_column The name of the column we want to change
 * @param array $column_info An array of info about the "new" column definition (see {@link smf_db_create_table()})
 * @return bool
 */
function smf_db_change_column($table_name, $old_column, $column_info)
{
    global $smcFunc, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // Check it does exist!
    $columns = $smcFunc['db_list_columns']($table_name, true);
    $old_info = null;
    foreach ($columns as $column)
        if ($column['name'] == $old_column)
            $old_info = $column;

    // Nothing?
    if ($old_info == null)
        return false;

    // Get the right bits.
    if (!isset($column_info['name']))
        $column_info['name'] = $old_column;
    if (!isset($column_info['default']))
        $column_info['default'] = $old_info['default'];
    if (!isset($column_info['null']))
        $column_info['null'] = $old_info['null'];
    if (!isset($column_info['auto']))
        $column_info['auto'] = $old_info['auto'];
    if (!isset($column_info['type']))
        $column_info['type'] = $old_info['type'];
    if (!isset($column_info['size']) || !is_numeric($column_info['size']))
        $column_info['size'] = $old_info['size'];
    if (!isset($column_info['unsigned']) || !in_array($column_info['type'], array('int', 'tinyint', 'smallint', 'mediumint', 'bigint')))
        $column_info['unsigned'] = '';

    list ($type, $size) = $smcFunc['db_calculate_type']($column_info['type'], $column_info['size']);

    // Allow for unsigned integers (mysql only)
    $unsigned = in_array($type, array('int', 'tinyint', 'smallint', 'mediumint', 'bigint')) && !empty($column_info['unsigned']) ? 'unsigned ' : '';

    if ($size !== null)
        $type = $type . '(' . $size . ')';

    $smcFunc['db_query']('', '
        ALTER TABLE ' . $table_name . '
        CHANGE COLUMN `' . $old_column . '` `' . $column_info['name'] . '` ' . $type . ' ' . (!empty($unsigned) ? $unsigned : '') . (empty($column_info['null']) ? 'NOT NULL' : '') . ' ' .
            (!isset($column_info['default']) ? '' : 'default \'' . $smcFunc['db_escape_string']($column_info['default']) . '\'') . ' ' .
            (empty($column_info['auto']) ? '' : 'auto_increment') . ' ',
        array(
            'security_override' => true,
        )
    );
}

/**
 * Add an index.
 *
 * @param string $table_name The name of the table to add the index to
 * @param array $index_info An array of index info (see {@link smf_db_create_table()})
 * @param array $parameters Not used?
 * @param string $if_exists What to do if the index exists. If 'update', the definition will be updated.
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_add_index($table_name, $index_info, $parameters = array(), $if_exists = 'update', $error = 'fatal')
{
    global $smcFunc, $db_package_log, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // No columns = no index.
    if (empty($index_info['columns']))
        return false;
    $columns = implode(',', $index_info['columns']);

    // No name - make it up!
    if (empty($index_info['name']))
    {
        // No need for primary.
        if (isset($index_info['type']) && $index_info['type'] == 'primary')
            $index_info['name'] = '';
        else
            $index_info['name'] = implode('_', $index_info['columns']);
    }

    // Log that we are going to want to remove this!
    $db_package_log[] = array('remove_index', $table_name, $index_info['name']);

    // Let's get all our indexes.
    $indexes = $smcFunc['db_list_indexes']($table_name, true);
    // Do we already have it?
    foreach ($indexes as $index)
    {
        if ($index['name'] == $index_info['name'] || ($index['type'] == 'primary' && isset($index_info['type']) && $index_info['type'] == 'primary'))
        {
            // If we want to overwrite simply remove the current one then continue.
            if ($if_exists != 'update' || $index['type'] == 'primary')
                return false;
            else
                $smcFunc['db_remove_index']($table_name, $index_info['name']);
        }
    }

    // If we're here we know we don't have the index - so just add it.
    if (!empty($index_info['type']) && $index_info['type'] == 'primary')
    {
        $smcFunc['db_query']('', '
            ALTER TABLE ' . $table_name . '
            ADD PRIMARY KEY (' . $columns . ')',
            array(
                'security_override' => true,
            )
        );
    }
    else
    {
        $smcFunc['db_query']('', '
            ALTER TABLE ' . $table_name . '
            ADD ' . (isset($index_info['type']) && $index_info['type'] == 'unique' ? 'UNIQUE' : 'INDEX') . ' ' . $index_info['name'] . ' (' . $columns . ')',
            array(
                'security_override' => true,
            )
        );
    }
}

/**
 * Remove an index.
 *
 * @param string $table_name The name of the table to remove the index from
 * @param string $index_name The name of the index to remove
 * @param array $parameters Not used?
 * @param string $error
 * @return boolean Whether or not the operation was successful
 */
function smf_db_remove_index($table_name, $index_name, $parameters = array(), $error = 'fatal')
{
    global $smcFunc, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // Better exist!
    $indexes = $smcFunc['db_list_indexes']($table_name, true);

    foreach ($indexes as $index)
    {
        // If the name is primary we want the primary key!
        if ($index['type'] == 'primary' && $index_name == 'primary')
        {
            // Dropping primary key?
            $smcFunc['db_query']('', '
                ALTER TABLE ' . $table_name . '
                DROP PRIMARY KEY',
                array(
                    'security_override' => true,
                )
            );

            return true;
        }
        if ($index['name'] == $index_name)
        {
            // Drop the bugger...
            $smcFunc['db_query']('', '
                ALTER TABLE ' . $table_name . '
                DROP INDEX ' . $index_name,
                array(
                    'security_override' => true,
                )
            );

            return true;
        }
    }

    // Not to be found ;(
    return false;
}

/**
 * Get the schema formatted name for a type.
 *
 * @param string $type_name The data type (int, varchar, smallint, etc.)
 * @param int $type_size The size (8, 255, etc.)
 * @param boolean $reverse
 * @return array An array containing the appropriate type and size for this DB type
 */
function smf_db_calculate_type($type_name, $type_size = null, $reverse = false)
{
    // MySQL is actually the generic baseline.

    $type_name = strtolower($type_name);
    // Generic => Specific.
    if (!$reverse)
    {
        $types = array(
            'inet' => 'varbinary',
        );
    }
    else
    {
        $types = array(
            'varbinary' => 'inet',
        );
    }

    // Got it? Change it!
    if (isset($types[$type_name]))
    {
        if ($type_name == 'inet' && !$reverse)
        {
            $type_size = 16;
            $type_name = 'varbinary';
        }
        elseif ($type_name == 'varbinary' && $reverse && $type_size == 16)
        {
            $type_name = 'inet';
            $type_size = null;
        }
        elseif ($type_name == 'varbinary')
            $type_name = 'varbinary';
        else
            $type_name = $types[$type_name];
    }
    elseif ($type_name == 'boolean')
        $type_size = null;

    return array($type_name, $type_size);
}

/**
 * Get table structure.
 *
 * @param string $table_name The name of the table
 * @return array An array of table structure - the name, the column info from {@link smf_db_list_columns()} and the index info from {@link smf_db_list_indexes()}
 */
function smf_db_table_structure($table_name)
{
    global $smcFunc, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    // Find the table engine and add that to the info as well
    $table_status = $smcFunc['db_query']('', '
        SHOW TABLE STATUS
        LIKE {string:table}',
        array(
            'table' => strtr($table_name, array('_' => '\\_', '%' => '\\%'))
        )
    );

    // Only one row, so no need for a loop...
    $row = $smcFunc['db_fetch_assoc']($table_status);

    $smcFunc['db_free_result']($table_status);

    return array(
        'name' => $table_name,
        'columns' => $smcFunc['db_list_columns']($table_name, true),
        'indexes' => $smcFunc['db_list_indexes']($table_name, true),
        'engine' => $row['Engine'],
    );
}

/**
 * Return column information for a table.
 *
 * @param string $table_name The name of the table to get column info for
 * @param bool $detail Whether or not to return detailed info. If true, returns the column info. If false, just returns the column names.
 * @param array $parameters Not used?
 * @return array An array of column names or detailed column info, depending on $detail
 */
function smf_db_list_columns($table_name, $detail = false, $parameters = array())
{
    global $smcFunc, $db_prefix, $db_name;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    $result = $smcFunc['db_query']('', '
        SELECT column_name "Field", COLUMN_TYPE "Type", is_nullable "Null", COLUMN_KEY "Key" , column_default "Default", extra "Extra"
        FROM information_schema.columns
        WHERE table_name = {string:table_name}
            AND table_schema = {string:db_name}
        ORDER BY ordinal_position',
        array(
            'table_name' => $table_name,
            'db_name' => $db_name,
        )
    );
    $columns = array();
    while ($row = $smcFunc['db_fetch_assoc']($result))
    {
        if (!$detail)
        {
            $columns[] = $row['Field'];
        }
        else
        {
            // Is there an auto_increment?
            $auto = strpos($row['Extra'], 'auto_increment') !== false ? true : false;

            // Can we split out the size?
            if (preg_match('~(.+?)\s*\((\d+)\)(?:(?:\s*)?(unsigned))?~i', $row['Type'], $matches) === 1)
            {
                $type = $matches[1];
                $size = $matches[2];
                if (!empty($matches[3]) && $matches[3] == 'unsigned')
                    $unsigned = true;
            }
            else
            {
                $type = $row['Type'];
                $size = null;
            }

            $columns[$row['Field']] = array(
                'name' => $row['Field'],
                'null' => $row['Null'] != 'YES' ? false : true,
                'default' => isset($row['Default']) ? $row['Default'] : null,
                'type' => $type,
                'size' => $size,
                'auto' => $auto,
            );

            if (isset($unsigned))
            {
                $columns[$row['Field']]['unsigned'] = $unsigned;
                unset($unsigned);
            }
        }
    }
    $smcFunc['db_free_result']($result);

    return $columns;
}

/**
 * Get index information.
 *
 * @param string $table_name The name of the table to get indexes for
 * @param bool $detail Whether or not to return detailed info.
 * @param array $parameters Not used?
 * @return array An array of index names or a detailed array of index info, depending on $detail
 */
function smf_db_list_indexes($table_name, $detail = false, $parameters = array())
{
    global $smcFunc, $db_prefix;

    $table_name = str_replace('{db_prefix}', $db_prefix, $table_name);

    $result = $smcFunc['db_query']('', '
        SHOW KEYS
        FROM {raw:table_name}',
        array(
            'table_name' => substr($table_name, 0, 1) == '`' ? $table_name : '`' . $table_name . '`',
        )
    );
    $indexes = array();
    while ($row = $smcFunc['db_fetch_assoc']($result))
    {
        if (!$detail)
            $indexes[] = $row['Key_name'];
        else
        {
            // What is the type?
            if ($row['Key_name'] == 'PRIMARY')
                $type = 'primary';
            elseif (empty($row['Non_unique']))
                $type = 'unique';
            elseif (isset($row['Index_type']) && $row['Index_type'] == 'FULLTEXT')
                $type = 'fulltext';
            else
                $type = 'index';

            // This is the first column we've seen?
            if (empty($indexes[$row['Key_name']]))
            {
                $indexes[$row['Key_name']] = array(
                    'name' => $row['Key_name'],
                    'type' => $type,
                    'columns' => array(),
                );
            }

            // Is it a partial index?
            if (!empty($row['Sub_part']))
                $indexes[$row['Key_name']]['columns'][] = $row['Column_name'] . '(' . $row['Sub_part'] . ')';
            else
                $indexes[$row['Key_name']]['columns'][] = $row['Column_name'];
        }
    }
    $smcFunc['db_free_result']($result);

    return $indexes;
}

/**
 * Creates a query for a column
 *
 * @param array $column An array of column info
 * @return string The column definition
 */
function smf_db_create_query_column($column)
{
    global $smcFunc;

    // Auto increment is easy here!
    if (!empty($column['auto']))
    {
        $default = 'auto_increment';
    }
    elseif (isset($column['default']) && $column['default'] !== null)
        $default = 'default \'' . $smcFunc['db_escape_string']($column['default']) . '\'';
    else
        $default = '';

    // Sort out the size... and stuff...
    $column['size'] = isset($column['size']) && is_numeric($column['size']) ? $column['size'] : null;
    list ($type, $size) = $smcFunc['db_calculate_type']($column['type'], $column['size']);

    // Allow unsigned integers (mysql only)
    $unsigned = in_array($type, array('int', 'tinyint', 'smallint', 'mediumint', 'bigint')) && !empty($column['unsigned']) ? 'unsigned ' : '';

    if ($size !== null)
        $type = $type . '(' . $size . ')';

    // Now just put it together!
    return '`' . $column['name'] . '` ' . $type . ' ' . (!empty($unsigned) ? $unsigned : '') . (!empty($column['null']) ? '' : 'NOT NULL') . ' ' . $default;
}

?>