// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qsql_mysql_p.h"

#include <qcoreapplication.h>
#include <qvariant.h>
#include <qvarlengtharray.h>
#include <qdatetime.h>
#include <qdebug.h>
#include <qfile.h>
#include <qlist.h>
#include <qloggingcategory.h>
#include <qsqlerror.h>
#include <qsqlfield.h>
#include <qsqlindex.h>
#include <qsqlquery.h>
#include <qsqlrecord.h>
#include <qstringlist.h>
#include <qtimezone.h>
#include <QtSql/private/qsqldriver_p.h>
#include <QtSql/private/qsqlresult_p.h>

#ifdef Q_OS_WIN32
// comment the next line out if you want to use MySQL/embedded on Win32 systems.
// note that it will crash if you don't statically link to the mysql/e library!
# define Q_NO_MYSQL_EMBEDDED
#endif

Q_DECLARE_METATYPE(MYSQL_RES*)
Q_DECLARE_METATYPE(MYSQL*)
Q_DECLARE_METATYPE(MYSQL_STMT*)

// MYSQL_TYPE_JSON was introduced with MySQL 5.7.9
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID < 50709
#define MYSQL_TYPE_JSON  245
#endif

// MySQL above version 8 removed my_bool typedef while MariaDB kept it,
// by redefining it we can regain source compatibility.
using my_bool = decltype(mysql_stmt_bind_result(nullptr, nullptr));

// this is a copy of the old MYSQL_TIME before an additional integer was added in
// 8.0.27.0. This kills the sanity check during retrieving this struct from mysql
// when another libmysql version is used during runtime than during compile time
struct QT_MYSQL_TIME
{
    unsigned int year, month, day, hour, minute, second;
    unsigned long second_part; /**< microseconds */
    my_bool neg;
    enum enum_mysql_timestamp_type time_type;
};

QT_BEGIN_NAMESPACE

static Q_LOGGING_CATEGORY(lcMysql, "qt.sql.mysql")

using namespace Qt::StringLiterals;

class QMYSQLDriverPrivate : public QSqlDriverPrivate
{
    Q_DECLARE_PUBLIC(QMYSQLDriver)

public:
    QMYSQLDriverPrivate() : QSqlDriverPrivate(QSqlDriver::MySqlServer)
    {}
    MYSQL *mysql = nullptr;
    QString dbName;
    bool preparedQuerysEnabled = false;
};

static inline QVariant qDateFromString(const QString &val)
{
#if !QT_CONFIG(datestring)
    Q_UNUSED(val);
    return QVariant(val);
#else
    if (val.isEmpty())
        return QVariant(QDate());
    return QVariant(QDate::fromString(val, Qt::ISODate));
#endif
}

static inline QVariant qTimeFromString(const QString &val)
{
#if !QT_CONFIG(datestring)
    Q_UNUSED(val);
    return QVariant(val);
#else
    if (val.isEmpty())
        return QVariant(QTime());
    return QVariant(QTime::fromString(val, Qt::ISODate));
#endif
}

static inline QVariant qDateTimeFromString(QString &val)
{
#if !QT_CONFIG(datestring)
    Q_UNUSED(val);
    return QVariant(val);
#else
    if (val.isEmpty())
        return QVariant(QDateTime());

    // TIMESTAMPS have either the format "yyyyMMddhhmmss" or "yyyy-MM-dd
    // hh:mm:ss". QDateTime::fromString() can convert the latter, but not the
    // former, so adapt it if necessary.
    if (val.size() == 14)
        val.insert(4, u'-').insert(7, u'-').insert(10, u'T').insert(13, u':').insert(16, u':');

    if (!val.endsWith(u'Z'))
        val.append(u'Z');       // make UTC
    return QVariant(QDateTime::fromString(val, Qt::ISODate));
#endif
}

// check if this client and server version of MySQL/MariaDB support prepared statements
static inline bool checkPreparedQueries(MYSQL *mysql)
{
    std::unique_ptr<MYSQL_STMT, decltype(&mysql_stmt_close)> stmt(mysql_stmt_init(mysql), &mysql_stmt_close);
    if (!stmt)
        return false;

    static const char dummyQuery[] = "SELECT ? + ?";
    if (mysql_stmt_prepare(stmt.get(), dummyQuery, sizeof(dummyQuery) - 1))
        return false;

    return mysql_stmt_param_count(stmt.get()) == 2;
}

// used with prepared queries and bound arguments
static inline void setUtcTimeZone(MYSQL *mysql)
{
    std::unique_ptr<MYSQL_STMT, decltype(&mysql_stmt_close)> stmt(mysql_stmt_init(mysql), &mysql_stmt_close);
    if (!stmt)
        return;

    static const char query[] = "SET time_zone = '+00:00'";
    if (mysql_stmt_prepare(stmt.get(), query, sizeof(query) - 1))
        mysql_stmt_execute(stmt.get());
}

class QMYSQLResultPrivate;

class QMYSQLResult : public QSqlResult
{
    Q_DECLARE_PRIVATE(QMYSQLResult)
    friend class QMYSQLDriver;

public:
    explicit QMYSQLResult(const QMYSQLDriver *db);
    ~QMYSQLResult();

    QVariant handle() const override;
protected:
    void cleanup();
    bool fetch(int i) override;
    bool fetchNext() override;
    bool fetchLast() override;
    bool fetchFirst() override;
    QVariant data(int field) override;
    bool isNull(int field) override;
    bool reset (const QString& query) override;
    int size() override;
    int numRowsAffected() override;
    QVariant lastInsertId() const override;
    QSqlRecord record() const override;
    void virtual_hook(int id, void *data) override;
    bool nextResult() override;
    void detachFromResultSet() override;

    bool prepare(const QString &stmt) override;
    bool exec() override;
};

class QMYSQLResultPrivate: public QSqlResultPrivate
{
    Q_DECLARE_PUBLIC(QMYSQLResult)

public:
    Q_DECLARE_SQLDRIVER_PRIVATE(QMYSQLDriver)

    using QSqlResultPrivate::QSqlResultPrivate;

    bool bindInValues();
    void bindBlobs();

    MYSQL_RES *result = nullptr;
    MYSQL_ROW row;

    struct QMyField
    {
        char *outField = nullptr;
        const MYSQL_FIELD *myField = nullptr;
        QMetaType type = QMetaType();
        my_bool nullIndicator = false;
        ulong bufLength = 0ul;
    };

    QList<QMyField> fields;

    MYSQL_STMT *stmt = nullptr;
    MYSQL_RES *meta = nullptr;

    MYSQL_BIND *inBinds = nullptr;
    MYSQL_BIND *outBinds = nullptr;

    int rowsAffected = 0;
    bool hasBlobs = false;
    bool preparedQuery = false;
};

static QSqlError qMakeError(const QString &err, QSqlError::ErrorType type,
                            const QMYSQLDriverPrivate *p)
{
    const char *cerr = p->mysql ? mysql_error(p->mysql) : nullptr;
    return QSqlError("QMYSQL: "_L1 + err,
                     QString::fromUtf8(cerr),
                     type, QString::number(mysql_errno(p->mysql)));
}


static QMetaType qDecodeMYSQLType(enum_field_types mysqltype, uint flags)
{
    QMetaType::Type type;
    switch (mysqltype) {
    case MYSQL_TYPE_TINY:
        type = (flags & UNSIGNED_FLAG) ? QMetaType::UChar : QMetaType::Char;
        break;
    case MYSQL_TYPE_SHORT:
        type = (flags & UNSIGNED_FLAG) ? QMetaType::UShort : QMetaType::Short;
        break;
    case MYSQL_TYPE_LONG:
    case MYSQL_TYPE_INT24:
        type = (flags & UNSIGNED_FLAG) ? QMetaType::UInt : QMetaType::Int;
        break;
    case MYSQL_TYPE_YEAR:
        type = QMetaType::Int;
        break;
    case MYSQL_TYPE_BIT:
    case MYSQL_TYPE_LONGLONG:
        type = (flags & UNSIGNED_FLAG) ? QMetaType::ULongLong : QMetaType::LongLong;
        break;
    case MYSQL_TYPE_FLOAT:
    case MYSQL_TYPE_DOUBLE:
    case MYSQL_TYPE_DECIMAL:
    case MYSQL_TYPE_NEWDECIMAL:
        type = QMetaType::Double;
        break;
    case MYSQL_TYPE_DATE:
        type = QMetaType::QDate;
        break;
    case MYSQL_TYPE_TIME:
        // A time field can be within the range '-838:59:59' to '838:59:59' so
        // use QString instead of QTime since QTime is limited to 24 hour clock
        type = QMetaType::QString;
        break;
    case MYSQL_TYPE_DATETIME:
    case MYSQL_TYPE_TIMESTAMP:
        type = QMetaType::QDateTime;
        break;
    case MYSQL_TYPE_STRING:
    case MYSQL_TYPE_VAR_STRING:
    case MYSQL_TYPE_BLOB:
    case MYSQL_TYPE_TINY_BLOB:
    case MYSQL_TYPE_MEDIUM_BLOB:
    case MYSQL_TYPE_LONG_BLOB:
    case MYSQL_TYPE_GEOMETRY:
    case MYSQL_TYPE_JSON:
        type = (flags & BINARY_FLAG) ? QMetaType::QByteArray : QMetaType::QString;
        break;
    case MYSQL_TYPE_ENUM:
    case MYSQL_TYPE_SET:
        type = QMetaType::QString;
        break;
    default:  // needed because there are more enum values which are not available in all headers
        type = QMetaType::QString;
        break;
    }
    return QMetaType(type);
}

static QSqlField qToField(MYSQL_FIELD *field)
{
    QSqlField f(QString::fromUtf8(field->name),
                qDecodeMYSQLType(field->type, field->flags),
                QString::fromUtf8(field->table));
    f.setRequired(IS_NOT_NULL(field->flags));
    f.setLength(field->length);
    f.setPrecision(field->decimals);
    f.setAutoValue(field->flags & AUTO_INCREMENT_FLAG);
    return f;
}

static QSqlError qMakeStmtError(const QString &err, QSqlError::ErrorType type,
                                 MYSQL_STMT *stmt)
{
    const char *cerr = mysql_stmt_error(stmt);
    return QSqlError("QMYSQL: "_L1 + err,
                     QString::fromLatin1(cerr),
                     type, QString::number(mysql_stmt_errno(stmt)));
}

static bool qIsBlob(enum_field_types t)
{
    return t == MYSQL_TYPE_TINY_BLOB
           || t == MYSQL_TYPE_BLOB
           || t == MYSQL_TYPE_MEDIUM_BLOB
           || t == MYSQL_TYPE_LONG_BLOB
           || t == MYSQL_TYPE_JSON;
}

static bool qIsTimeOrDate(enum_field_types t)
{
    // *not* MYSQL_TYPE_TIME because its range is bigger than QTime
    // (see above)
    return t == MYSQL_TYPE_DATE || t == MYSQL_TYPE_DATETIME || t == MYSQL_TYPE_TIMESTAMP;
}

static bool qIsInteger(int t)
{
    return t == QMetaType::Char || t == QMetaType::UChar
        || t == QMetaType::Short || t == QMetaType::UShort
        || t == QMetaType::Int || t == QMetaType::UInt
        || t == QMetaType::LongLong || t == QMetaType::ULongLong;
}

static inline bool qIsBitfield(enum_field_types type)
{
    return type == MYSQL_TYPE_BIT;
}

void QMYSQLResultPrivate::bindBlobs()
{
    for (int i = 0; i < fields.size(); ++i) {
        const MYSQL_FIELD *fieldInfo = fields.at(i).myField;
        if (qIsBlob(inBinds[i].buffer_type) && meta && fieldInfo) {
            MYSQL_BIND *bind = &inBinds[i];
            bind->buffer_length = fieldInfo->max_length;
            delete[] static_cast<char*>(bind->buffer);
            bind->buffer = new char[fieldInfo->max_length];
            fields[i].outField = static_cast<char*>(bind->buffer);
        }
    }
}

bool QMYSQLResultPrivate::bindInValues()
{
    if (!meta)
        meta = mysql_stmt_result_metadata(stmt);
    if (!meta)
        return false;

    fields.resize(mysql_num_fields(meta));

    inBinds = new MYSQL_BIND[fields.size()];
    memset(inBinds, 0, fields.size() * sizeof(MYSQL_BIND));

    const MYSQL_FIELD *fieldInfo;

    int i = 0;
    while((fieldInfo = mysql_fetch_field(meta))) {
        MYSQL_BIND *bind = &inBinds[i];

        QMyField &f = fields[i];
        f.myField = fieldInfo;
        bind->buffer_length = f.bufLength = fieldInfo->length + 1;
        bind->buffer_type = fieldInfo->type;
        f.type = qDecodeMYSQLType(fieldInfo->type, fieldInfo->flags);
        if (qIsBlob(fieldInfo->type)) {
            // the size of a blob-field is available as soon as we call
            // mysql_stmt_store_result()
            // after mysql_stmt_exec() in QMYSQLResult::exec()
            bind->buffer_length = f.bufLength = 0;
            hasBlobs = true;
        } else if (qIsTimeOrDate(fieldInfo->type)) {
            bind->buffer_length = f.bufLength = sizeof(QT_MYSQL_TIME);
        } else if (qIsInteger(f.type.id())) {
            bind->buffer_length = f.bufLength = 8;
        } else {
            bind->buffer_type = MYSQL_TYPE_STRING;
        }

        bind->is_null = &f.nullIndicator;
        bind->length = &f.bufLength;
        bind->is_unsigned = fieldInfo->flags & UNSIGNED_FLAG ? 1 : 0;

        char *field = bind->buffer_length ? new char[bind->buffer_length + 1]{} : nullptr;
        bind->buffer = f.outField = field;

        ++i;
    }
    return true;
}

QMYSQLResult::QMYSQLResult(const QMYSQLDriver* db)
    : QSqlResult(*new QMYSQLResultPrivate(this, db))
{
}

QMYSQLResult::~QMYSQLResult()
{
    cleanup();
}

QVariant QMYSQLResult::handle() const
{
    Q_D(const QMYSQLResult);
    if (d->preparedQuery)
        return d->meta ? QVariant::fromValue(d->meta) : QVariant::fromValue(d->stmt);
    else
        return QVariant::fromValue(d->result);
}

void QMYSQLResult::cleanup()
{
    Q_D(QMYSQLResult);
    if (d->result)
        mysql_free_result(d->result);

// must iterate through leftover result sets from multi-selects or stored procedures
// if this isn't done subsequent queries will fail with "Commands out of sync"
    while (driver() && d->drv_d_func()->mysql && mysql_next_result(d->drv_d_func()->mysql) == 0) {
        MYSQL_RES *res = mysql_store_result(d->drv_d_func()->mysql);
        if (res)
            mysql_free_result(res);
    }

    if (d->stmt) {
        if (mysql_stmt_close(d->stmt))
            qCWarning(lcMysql, "QMYSQLResult::cleanup: unable to free statement handle");
        d->stmt = 0;
    }

    if (d->meta) {
        mysql_free_result(d->meta);
        d->meta = 0;
    }

    for (const QMYSQLResultPrivate::QMyField &f : std::as_const(d->fields))
        delete[] f.outField;

    if (d->outBinds) {
        delete[] d->outBinds;
        d->outBinds = 0;
    }

    if (d->inBinds) {
        delete[] d->inBinds;
        d->inBinds = 0;
    }

    d->hasBlobs = false;
    d->fields.clear();
    d->result = nullptr;
    d->row = nullptr;
    setAt(-1);
    setActive(false);
}

bool QMYSQLResult::fetch(int i)
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;
    if (isForwardOnly()) { // fake a forward seek
        if (at() < i) {
            int x = i - at();
            while (--x && fetchNext()) {};
            return fetchNext();
        } else {
            return false;
        }
    }
    if (at() == i)
        return true;
    if (d->preparedQuery) {
        mysql_stmt_data_seek(d->stmt, i);

        int nRC = mysql_stmt_fetch(d->stmt);
        if (nRC) {
            if (nRC == 1 || nRC == MYSQL_DATA_TRUNCATED)
                setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                         "Unable to fetch data"), QSqlError::StatementError, d->stmt));
            return false;
        }
    } else {
        mysql_data_seek(d->result, i);
        d->row = mysql_fetch_row(d->result);
        if (!d->row)
            return false;
    }

    setAt(i);
    return true;
}

bool QMYSQLResult::fetchNext()
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;
    if (d->preparedQuery) {
        int nRC = mysql_stmt_fetch(d->stmt);
        if (nRC) {
            if (nRC == 1 || nRC == MYSQL_DATA_TRUNCATED)
                setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                                    "Unable to fetch data"), QSqlError::StatementError, d->stmt));
            return false;
        }
    } else {
        d->row = mysql_fetch_row(d->result);
        if (!d->row)
            return false;
    }
    setAt(at() + 1);
    return true;
}

bool QMYSQLResult::fetchLast()
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;
    if (isForwardOnly()) { // fake this since MySQL can't seek on forward only queries
        bool success = fetchNext(); // did we move at all?
        while (fetchNext()) {};
        return success;
    }

    my_ulonglong numRows = d->preparedQuery ? mysql_stmt_num_rows(d->stmt) : mysql_num_rows(d->result);
    if (at() == int(numRows))
        return true;
    if (!numRows)
        return false;
    return fetch(numRows - 1);
}

bool QMYSQLResult::fetchFirst()
{
    if (at() == 0)
        return true;

    if (isForwardOnly())
        return (at() == QSql::BeforeFirstRow) ? fetchNext() : false;
    return fetch(0);
}

static inline uint64_t
qDecodeBitfield(const QMYSQLResultPrivate::QMyField &f, const char *outField)
{
    // byte-aligned length
    const auto numBytes = (f.myField->length + 7) / 8;
    uint64_t val = 0;
    for (unsigned long i = 0; i < numBytes && outField; ++i) {
        uint64_t tmp = static_cast<uint8_t>(outField[i]);
        val <<= 8;
        val |= tmp;
    }
    return val;
}

QVariant QMYSQLResult::data(int field)
{
    Q_D(QMYSQLResult);
    if (!isSelect() || field >= d->fields.size()) {
        qCWarning(lcMysql, "QMYSQLResult::data: column %d out of range", field);
        return QVariant();
    }

    if (!driver())
        return QVariant();

    my_ulonglong fieldLength = 0;
    const QMYSQLResultPrivate::QMyField &f = d->fields.at(field);
    QString val;
    if (d->preparedQuery) {
        if (f.nullIndicator)
            return QVariant(f.type);
        if (qIsBitfield(f.myField->type)) {
            return QVariant::fromValue(qDecodeBitfield(f, f.outField));
        } else if (qIsInteger(f.type.id())) {
            QVariant variant(f.type, f.outField);
            // we never want to return char variants here, see QTBUG-53397
            if (f.type.id() == QMetaType::UChar)
                return variant.toUInt();
            else if (f.type.id() == QMetaType::Char)
                return variant.toInt();
            return variant;
        } else if (qIsTimeOrDate(f.myField->type) && f.bufLength >= sizeof(QT_MYSQL_TIME)) {
            auto t = reinterpret_cast<const QT_MYSQL_TIME *>(f.outField);
            QDate date;
            QTime time;
            if (f.type.id() != QMetaType::QTime)
                date = QDate(t->year, t->month, t->day);
            if (f.type.id() != QMetaType::QDate)
                time = QTime(t->hour, t->minute, t->second, t->second_part / 1000);
            if (f.type.id() == QMetaType::QDateTime)
                return QDateTime(date, time, QTimeZone::UTC);
            else if (f.type.id() == QMetaType::QDate)
                return date;
            else
                return time;
        }

        if (f.type.id() != QMetaType::QByteArray)
            val = QString::fromUtf8(f.outField, f.bufLength);
    } else {
        if (d->row[field] == nullptr) {
            // NULL value
            return QVariant(f.type);
        }

        if (qIsBitfield(f.myField->type))
            return QVariant::fromValue(qDecodeBitfield(f, d->row[field]));

        fieldLength = mysql_fetch_lengths(d->result)[field];

        if (f.type.id() != QMetaType::QByteArray)
            val = QString::fromUtf8(d->row[field], fieldLength);
    }

    switch (f.type.id()) {
    case QMetaType::LongLong:
        return QVariant(val.toLongLong());
    case QMetaType::ULongLong:
        return QVariant(val.toULongLong());
    case QMetaType::Char:
    case QMetaType::Short:
    case QMetaType::Int:
        return QVariant(val.toInt());
    case QMetaType::UChar:
    case QMetaType::UShort:
    case QMetaType::UInt:
        return QVariant(val.toUInt());
    case QMetaType::Double: {
        QVariant v;
        bool ok=false;
        double dbl = val.toDouble(&ok);
        switch(numericalPrecisionPolicy()) {
            case QSql::LowPrecisionInt32:
                v=QVariant(dbl).toInt();
                break;
            case QSql::LowPrecisionInt64:
                v = QVariant(dbl).toLongLong();
                break;
            case QSql::LowPrecisionDouble:
                v = QVariant(dbl);
                break;
            case QSql::HighPrecision:
            default:
                v = val;
                ok = true;
                break;
        }
        if (ok)
            return v;
        return QVariant();
    }
    case QMetaType::QDate:
        return qDateFromString(val);
    case QMetaType::QTime:
        return qTimeFromString(val);
    case QMetaType::QDateTime:
        return qDateTimeFromString(val);
    case QMetaType::QByteArray: {

        QByteArray ba;
        if (d->preparedQuery) {
            ba = QByteArray(f.outField, f.bufLength);
        } else {
            ba = QByteArray(d->row[field], fieldLength);
        }
        return QVariant(ba);
    }
    case QMetaType::QString:
    default:
        return QVariant(val);
    }
    Q_UNREACHABLE();
}

bool QMYSQLResult::isNull(int field)
{
   Q_D(const QMYSQLResult);
   if (field < 0 || field >= d->fields.size())
       return true;
   if (d->preparedQuery)
       return d->fields.at(field).nullIndicator;
   else
       return d->row[field] == nullptr;
}

bool QMYSQLResult::reset (const QString& query)
{
    Q_D(QMYSQLResult);
    if (!driver() || !driver()->isOpen() || driver()->isOpenError())
        return false;

    d->preparedQuery = false;

    cleanup();

    const QByteArray encQuery = query.toUtf8();
    if (mysql_real_query(d->drv_d_func()->mysql, encQuery.data(), encQuery.size())) {
        setLastError(qMakeError(QCoreApplication::translate("QMYSQLResult", "Unable to execute query"),
                     QSqlError::StatementError, d->drv_d_func()));
        return false;
    }
    d->result = mysql_store_result(d->drv_d_func()->mysql);
    if (!d->result && mysql_field_count(d->drv_d_func()->mysql) > 0) {
        setLastError(qMakeError(QCoreApplication::translate("QMYSQLResult", "Unable to store result"),
                    QSqlError::StatementError, d->drv_d_func()));
        return false;
    }
    int numFields = mysql_field_count(d->drv_d_func()->mysql);
    setSelect(numFields != 0);
    d->fields.resize(numFields);
    d->rowsAffected = mysql_affected_rows(d->drv_d_func()->mysql);

    if (isSelect()) {
        for(int i = 0; i < numFields; i++) {
            MYSQL_FIELD* field = mysql_fetch_field_direct(d->result, i);
            d->fields[i].type = qDecodeMYSQLType(field->type, field->flags);
            d->fields[i].myField = field;
        }
        setAt(QSql::BeforeFirstRow);
    }
    setActive(true);
    return isActive();
}

int QMYSQLResult::size()
{
    Q_D(const QMYSQLResult);
    if (driver() && isSelect())
        if (d->preparedQuery)
            return mysql_stmt_num_rows(d->stmt);
        else
            return int(mysql_num_rows(d->result));
    else
        return -1;
}

int QMYSQLResult::numRowsAffected()
{
    Q_D(const QMYSQLResult);
    return d->rowsAffected;
}

void QMYSQLResult::detachFromResultSet()
{
    Q_D(QMYSQLResult);

    if (d->preparedQuery) {
        mysql_stmt_free_result(d->stmt);
    }
}

QVariant QMYSQLResult::lastInsertId() const
{
    Q_D(const QMYSQLResult);
    if (!isActive() || !driver())
        return QVariant();

    if (d->preparedQuery) {
        quint64 id = mysql_stmt_insert_id(d->stmt);
        if (id)
            return QVariant(id);
    } else {
        quint64 id = mysql_insert_id(d->drv_d_func()->mysql);
        if (id)
            return QVariant(id);
    }
    return QVariant();
}

QSqlRecord QMYSQLResult::record() const
{
    Q_D(const QMYSQLResult);
    QSqlRecord info;
    MYSQL_RES *res;
    if (!isActive() || !isSelect() || !driver())
        return info;

    res = d->preparedQuery ? d->meta : d->result;

    if (!mysql_errno(d->drv_d_func()->mysql)) {
        mysql_field_seek(res, 0);
        MYSQL_FIELD* field = mysql_fetch_field(res);
        while (field) {
            info.append(qToField(field));
            field = mysql_fetch_field(res);
        }
    }
    mysql_field_seek(res, 0);
    return info;
}

bool QMYSQLResult::nextResult()
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;

    setAt(-1);
    setActive(false);

    if (d->result && isSelect())
        mysql_free_result(d->result);
    d->result = 0;
    setSelect(false);

    for (const QMYSQLResultPrivate::QMyField &f : std::as_const(d->fields))
        delete[] f.outField;
    d->fields.clear();

    int status = mysql_next_result(d->drv_d_func()->mysql);
    if (status > 0) {
        setLastError(qMakeError(QCoreApplication::translate("QMYSQLResult", "Unable to execute next query"),
                     QSqlError::StatementError, d->drv_d_func()));
        return false;
    } else if (status == -1) {
        return false;   // No more result sets
    }

    d->result = mysql_store_result(d->drv_d_func()->mysql);
    unsigned int numFields = mysql_field_count(d->drv_d_func()->mysql);
    if (!d->result && numFields > 0) {
        setLastError(qMakeError(QCoreApplication::translate("QMYSQLResult", "Unable to store next result"),
                     QSqlError::StatementError, d->drv_d_func()));
        return false;
    }

    setSelect(numFields > 0);
    d->fields.resize(numFields);
    d->rowsAffected = mysql_affected_rows(d->drv_d_func()->mysql);

    if (isSelect()) {
        for (unsigned int i = 0; i < numFields; i++) {
            MYSQL_FIELD *field = mysql_fetch_field_direct(d->result, i);
            d->fields[i].type = qDecodeMYSQLType(field->type, field->flags);
            d->fields[i].myField = field;
        }
    }

    setActive(true);
    return true;
}

void QMYSQLResult::virtual_hook(int id, void *data)
{
    QSqlResult::virtual_hook(id, data);
}

bool QMYSQLResult::prepare(const QString& query)
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;

    cleanup();
    if (!d->drv_d_func()->preparedQuerysEnabled)
        return QSqlResult::prepare(query);

    int r;

    if (query.isEmpty())
        return false;

    if (!d->stmt)
        d->stmt = mysql_stmt_init(d->drv_d_func()->mysql);
    if (!d->stmt) {
        setLastError(qMakeError(QCoreApplication::translate("QMYSQLResult", "Unable to prepare statement"),
                     QSqlError::StatementError, d->drv_d_func()));
        return false;
    }

    const QByteArray encQuery = query.toUtf8();
    r = mysql_stmt_prepare(d->stmt, encQuery.constData(), encQuery.size());
    if (r != 0) {
        setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                     "Unable to prepare statement"), QSqlError::StatementError, d->stmt));
        cleanup();
        return false;
    }

    const auto paramCount = mysql_stmt_param_count(d->stmt);
    if (paramCount > 0) // allocate memory for outvalues
        d->outBinds = new MYSQL_BIND[paramCount]();

    setSelect(d->bindInValues());
    d->preparedQuery = true;
    return true;
}

bool QMYSQLResult::exec()
{
    Q_D(QMYSQLResult);
    if (!driver())
        return false;
    if (!d->preparedQuery)
        return QSqlResult::exec();
    if (!d->stmt)
        return false;

    int r = 0;
    QList<QT_MYSQL_TIME *> timeVector;
    QList<QByteArray> stringVector;
    QList<my_bool> nullVector;

    const QList<QVariant> values = boundValues();

    r = mysql_stmt_reset(d->stmt);
    if (r != 0) {
        setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                     "Unable to reset statement"), QSqlError::StatementError, d->stmt));
        return false;
    }

    const unsigned long paramCount = mysql_stmt_param_count(d->stmt);
    if (paramCount > 0 && paramCount == static_cast<size_t>(values.size())) {
        nullVector.resize(values.size());
        for (qsizetype i = 0; i < values.size(); ++i) {
            const QVariant &val = boundValues().at(i);
            void *data = const_cast<void *>(val.constData());

            MYSQL_BIND* currBind = &d->outBinds[i];

            nullVector[i] = static_cast<my_bool>(QSqlResultPrivate::isVariantNull(val));
            currBind->is_null = &nullVector[i];
            currBind->length = 0;
            currBind->is_unsigned = 0;

            switch (val.userType()) {
                case QMetaType::QByteArray:
                    currBind->buffer_type = MYSQL_TYPE_BLOB;
                    currBind->buffer = const_cast<char *>(val.toByteArray().constData());
                    currBind->buffer_length = val.toByteArray().size();
                    break;

                case QMetaType::QTime:
                case QMetaType::QDate:
                case QMetaType::QDateTime: {
                    auto myTime = new QT_MYSQL_TIME{};
                    timeVector.append(myTime);
                    currBind->buffer = myTime;

                    QDate date;
                    QTime time;
                    int type = val.userType();
                    if (type == QMetaType::QTime) {
                        time = val.toTime();
                        currBind->buffer_type = MYSQL_TYPE_TIME;
                        myTime->time_type = MYSQL_TIMESTAMP_TIME;
                    } else if (type == QMetaType::QDate) {
                        date = val.toDate();
                        currBind->buffer_type = MYSQL_TYPE_DATE;
                        myTime->time_type = MYSQL_TIMESTAMP_DATE;
                    } else {
                        QDateTime dt = val.toDateTime().toUTC();
                        date = dt.date();
                        time = dt.time();
                        currBind->buffer_type = MYSQL_TYPE_DATETIME;
                        myTime->time_type = MYSQL_TIMESTAMP_DATETIME;
                    }

                    if (type == QMetaType::QTime || type == QMetaType::QDateTime) {
                        myTime->hour = time.hour();
                        myTime->minute = time.minute();
                        myTime->second = time.second();
                        myTime->second_part = time.msec() * 1000;
                    }
                    if (type == QMetaType::QDate || type == QMetaType::QDateTime) {
                        myTime->year = date.year();
                        myTime->month = date.month();
                        myTime->day = date.day();
                    }
                    currBind->buffer_length = sizeof(QT_MYSQL_TIME);
                    currBind->length = 0;
                    break; }
                case QMetaType::UInt:
                case QMetaType::Int:
                    currBind->buffer_type = MYSQL_TYPE_LONG;
                    currBind->buffer = data;
                    currBind->buffer_length = sizeof(int);
                    currBind->is_unsigned = (val.userType() != QMetaType::Int);
                break;
                case QMetaType::Bool:
                    currBind->buffer_type = MYSQL_TYPE_TINY;
                    currBind->buffer = data;
                    currBind->buffer_length = sizeof(bool);
                    currBind->is_unsigned = false;
                    break;
                case QMetaType::Double:
                    currBind->buffer_type = MYSQL_TYPE_DOUBLE;
                    currBind->buffer = data;
                    currBind->buffer_length = sizeof(double);
                    break;
                case QMetaType::LongLong:
                case QMetaType::ULongLong:
                    currBind->buffer_type = MYSQL_TYPE_LONGLONG;
                    currBind->buffer = data;
                    currBind->buffer_length = sizeof(qint64);
                    currBind->is_unsigned = (val.userType() == QMetaType::ULongLong);
                    break;
                case QMetaType::QString:
                default: {
                    QByteArray ba = val.toString().toUtf8();
                    stringVector.append(ba);
                    currBind->buffer_type = MYSQL_TYPE_STRING;
                    currBind->buffer = const_cast<char *>(ba.constData());
                    currBind->buffer_length = ba.size();
                    break; }
            }
        }

#if defined(MARIADB_VERSION_ID) || MYSQL_VERSION_ID < 80300
        r = mysql_stmt_bind_param(d->stmt, d->outBinds);
#else
        r = mysql_stmt_bind_named_param(d->stmt, d->outBinds, paramCount, nullptr);
#endif
        if (r != 0) {
            setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                         "Unable to bind value"), QSqlError::StatementError, d->stmt));
            qDeleteAll(timeVector);
            return false;
        }
    }
    r = mysql_stmt_execute(d->stmt);

    qDeleteAll(timeVector);

    if (r != 0) {
        setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                     "Unable to execute statement"), QSqlError::StatementError, d->stmt));
        return false;
    }
    //if there is meta-data there is also data
    setSelect(d->meta);

    d->rowsAffected = mysql_stmt_affected_rows(d->stmt);

    if (isSelect()) {
        my_bool update_max_length = true;

        r = mysql_stmt_bind_result(d->stmt, d->inBinds);
        if (r != 0) {
            setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                         "Unable to bind outvalues"), QSqlError::StatementError, d->stmt));
            return false;
        }
        if (d->hasBlobs)
            mysql_stmt_attr_set(d->stmt, STMT_ATTR_UPDATE_MAX_LENGTH, &update_max_length);

        r = mysql_stmt_store_result(d->stmt);
        if (r != 0) {
            setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                         "Unable to store statement results"), QSqlError::StatementError, d->stmt));
            return false;
        }

        if (d->hasBlobs) {
            // mysql_stmt_store_result() with STMT_ATTR_UPDATE_MAX_LENGTH set to true crashes
            // when called without a preceding call to mysql_stmt_bind_result()
            // in versions < 4.1.8
            d->bindBlobs();
            r = mysql_stmt_bind_result(d->stmt, d->inBinds);
            if (r != 0) {
                setLastError(qMakeStmtError(QCoreApplication::translate("QMYSQLResult",
                             "Unable to bind outvalues"), QSqlError::StatementError, d->stmt));
                return false;
            }
        }
        setAt(QSql::BeforeFirstRow);
    }
    setActive(true);
    return true;
}

/////////////////////////////////////////////////////////

static int qMySqlConnectionCount = 0;
static bool qMySqlInitHandledByUser = false;

static void qLibraryInit()
{
#ifndef Q_NO_MYSQL_EMBEDDED
    if (qMySqlInitHandledByUser || qMySqlConnectionCount > 1)
        return;

    if (mysql_library_init(0, 0, 0)) {
        qCWarning(lcMysql, "QMYSQLDriver::qServerInit: unable to start server.");
    }
#endif // Q_NO_MYSQL_EMBEDDED

#if defined(MARIADB_BASE_VERSION) || defined(MARIADB_VERSION_ID)
    qAddPostRoutine([]() { mysql_server_end(); });
#endif
}

static void qLibraryEnd()
{
#if !defined(MARIADB_BASE_VERSION) && !defined(MARIADB_VERSION_ID)
# if !defined(Q_NO_MYSQL_EMBEDDED)
    mysql_library_end();
# endif
#endif
}

QMYSQLDriver::QMYSQLDriver(QObject * parent)
    : QSqlDriver(*new QMYSQLDriverPrivate, parent)
{
    init();
    qLibraryInit();
}

/*!
    Create a driver instance with the open connection handle, \a con.
    The instance's parent (owner) is \a parent.
*/

QMYSQLDriver::QMYSQLDriver(MYSQL * con, QObject * parent)
    : QSqlDriver(*new QMYSQLDriverPrivate, parent)
{
    Q_D(QMYSQLDriver);
    init();
    if (con) {
        d->mysql = con;
        setOpen(true);
        setOpenError(false);
        if (qMySqlConnectionCount == 1)
            qMySqlInitHandledByUser = true;
    } else {
        qLibraryInit();
    }
}

void QMYSQLDriver::init()
{
    Q_D(QMYSQLDriver);
    d->mysql = 0;
    qMySqlConnectionCount++;
}

QMYSQLDriver::~QMYSQLDriver()
{
    qMySqlConnectionCount--;
    if (qMySqlConnectionCount == 0 && !qMySqlInitHandledByUser)
        qLibraryEnd();
}

bool QMYSQLDriver::hasFeature(DriverFeature f) const
{
    Q_D(const QMYSQLDriver);
    switch (f) {
    case Transactions:
        if (d->mysql) {
            if ((d->mysql->server_capabilities & CLIENT_TRANSACTIONS) == CLIENT_TRANSACTIONS)
                return true;
        }
        return false;
    case NamedPlaceholders:
    case BatchOperations:
    case SimpleLocking:
    case EventNotifications:
    case FinishQuery:
    case CancelQuery:
        return false;
    case QuerySize:
    case BLOB:
    case LastInsertId:
    case Unicode:
    case LowPrecisionNumbers:
        return true;
    case PreparedQueries:
    case PositionalPlaceholders:
        return d->preparedQuerysEnabled;
    case MultipleResultSets:
        return true;
    }
    return false;
}

static void setOptionFlag(uint &optionFlags, QStringView opt)
{
    if (opt == "CLIENT_COMPRESS"_L1)
        optionFlags |= CLIENT_COMPRESS;
    else if (opt == "CLIENT_FOUND_ROWS"_L1)
        optionFlags |= CLIENT_FOUND_ROWS;
    else if (opt == "CLIENT_IGNORE_SPACE"_L1)
        optionFlags |= CLIENT_IGNORE_SPACE;
    else if (opt == "CLIENT_INTERACTIVE"_L1)
        optionFlags |= CLIENT_INTERACTIVE;
    else if (opt == "CLIENT_NO_SCHEMA"_L1)
        optionFlags |= CLIENT_NO_SCHEMA;
    else if (opt == "CLIENT_ODBC"_L1)
        optionFlags |= CLIENT_ODBC;
    else if (opt == "CLIENT_SSL"_L1)
        qCWarning(lcMysql, "QMYSQLDriver: MYSQL_OPT_SSL_KEY, MYSQL_OPT_SSL_CERT "
                           "and MYSQL_OPT_SSL_CA should be used instead of CLIENT_SSL.");
    else
        qCWarning(lcMysql, "QMYSQLDriver::open: Unknown connect option '%ls'",
                  qUtf16Printable(QString(opt)));
}

static bool setOptionString(MYSQL *mysql, mysql_option option, QStringView v)
{
    return mysql_options(mysql, option, v.toUtf8().constData()) == 0;
}

static bool setOptionInt(MYSQL *mysql, mysql_option option, QStringView v)
{
    bool bOk;
    const auto val = v.toInt(&bOk);
    return bOk ? mysql_options(mysql, option, &val) == 0 : false;
}

static bool setOptionBool(MYSQL *mysql, mysql_option option, QStringView v)
{
    bool val = (v.isEmpty() || v == "TRUE"_L1 || v == "1"_L1);
    return mysql_options(mysql, option, &val) == 0;
}

// MYSQL_OPT_SSL_MODE was introduced with MySQL 5.7.11
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID >= 50711 && !defined(MARIADB_VERSION_ID)
static bool setOptionSslMode(MYSQL *mysql, mysql_option option, QStringView v)
{
    mysql_ssl_mode sslMode = SSL_MODE_DISABLED;
    if (v == "DISABLED"_L1 || v == "SSL_MODE_DISABLED"_L1)
        sslMode = SSL_MODE_DISABLED;
    else if (v == "PREFERRED"_L1 || v == "SSL_MODE_PREFERRED"_L1)
        sslMode = SSL_MODE_PREFERRED;
    else if (v == "REQUIRED"_L1 || v == "SSL_MODE_REQUIRED"_L1)
        sslMode = SSL_MODE_REQUIRED;
    else if (v == "VERIFY_CA"_L1 || v == "SSL_MODE_VERIFY_CA"_L1)
        sslMode = SSL_MODE_VERIFY_CA;
    else if (v == "VERIFY_IDENTITY"_L1 || v == "SSL_MODE_VERIFY_IDENTITY"_L1)
        sslMode = SSL_MODE_VERIFY_IDENTITY;
    else
        qCWarning(lcMysql, "Unknown ssl mode '%ls' - using SSL_MODE_DISABLED",
                  qUtf16Printable(QString(v)));
    return mysql_options(mysql, option, &sslMode) == 0;
}
#endif

static bool setOptionProtocol(MYSQL *mysql, mysql_option option, QStringView v)
{
    mysql_protocol_type proto = MYSQL_PROTOCOL_DEFAULT;
    if (v == "TCP"_L1 || v == "MYSQL_PROTOCOL_TCP"_L1)
        proto = MYSQL_PROTOCOL_TCP;
    else if (v == "SOCKET"_L1 || v == "MYSQL_PROTOCOL_SOCKET"_L1)
        proto = MYSQL_PROTOCOL_SOCKET;
    else if (v == "PIPE"_L1 || v == "MYSQL_PROTOCOL_PIPE"_L1)
        proto = MYSQL_PROTOCOL_PIPE;
    else if (v == "MEMORY"_L1 || v == "MYSQL_PROTOCOL_MEMORY"_L1)
        proto = MYSQL_PROTOCOL_MEMORY;
    else if (v == "DEFAULT"_L1 || v == "MYSQL_PROTOCOL_DEFAULT"_L1)
        proto = MYSQL_PROTOCOL_DEFAULT;
    else
        qCWarning(lcMysql, "Unknown protocol '%ls' - using MYSQL_PROTOCOL_DEFAULT",
                  qUtf16Printable(QString(v)));
    return mysql_options(mysql, option, &proto) == 0;
}

bool QMYSQLDriver::open(const QString &db,
                        const QString &user,
                        const QString &password,
                        const QString &host,
                        int port,
                        const QString &connOpts)
{
    Q_D(QMYSQLDriver);
    if (isOpen())
        close();

    if (!(d->mysql = mysql_init(nullptr))) {
        setLastError(qMakeError(tr("Unable to allocate a MYSQL object"),
                     QSqlError::ConnectionError, d));
        setOpenError(true);
        return false;
    }

    typedef bool (*SetOptionFunc)(MYSQL*, mysql_option, QStringView);
    struct mysqloptions {
        QLatin1StringView key;
        mysql_option option;
        SetOptionFunc func;
    };
    const mysqloptions options[] = {
        {"SSL_KEY"_L1,                   MYSQL_OPT_SSL_KEY,         setOptionString},
        {"SSL_CERT"_L1,                  MYSQL_OPT_SSL_CERT,        setOptionString},
        {"SSL_CA"_L1,                    MYSQL_OPT_SSL_CA,          setOptionString},
        {"SSL_CAPATH"_L1,                MYSQL_OPT_SSL_CAPATH,      setOptionString},
        {"SSL_CIPHER"_L1,                MYSQL_OPT_SSL_CIPHER,      setOptionString},
        {"MYSQL_OPT_SSL_KEY"_L1,         MYSQL_OPT_SSL_KEY,         setOptionString},
        {"MYSQL_OPT_SSL_CERT"_L1,        MYSQL_OPT_SSL_CERT,        setOptionString},
        {"MYSQL_OPT_SSL_CA"_L1,          MYSQL_OPT_SSL_CA,          setOptionString},
        {"MYSQL_OPT_SSL_CAPATH"_L1,      MYSQL_OPT_SSL_CAPATH,      setOptionString},
        {"MYSQL_OPT_SSL_CIPHER"_L1,      MYSQL_OPT_SSL_CIPHER,      setOptionString},
        {"MYSQL_OPT_SSL_CRL"_L1,         MYSQL_OPT_SSL_CRL,         setOptionString},
        {"MYSQL_OPT_SSL_CRLPATH"_L1,     MYSQL_OPT_SSL_CRLPATH,     setOptionString},
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID >= 50710
        {"MYSQL_OPT_TLS_VERSION"_L1,     MYSQL_OPT_TLS_VERSION,     setOptionString},
#endif
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID >= 50711 && !defined(MARIADB_VERSION_ID)
        {"MYSQL_OPT_SSL_MODE"_L1,        MYSQL_OPT_SSL_MODE,        setOptionSslMode},
#endif
        {"MYSQL_OPT_CONNECT_TIMEOUT"_L1, MYSQL_OPT_CONNECT_TIMEOUT, setOptionInt},
        {"MYSQL_OPT_READ_TIMEOUT"_L1,    MYSQL_OPT_READ_TIMEOUT,    setOptionInt},
        {"MYSQL_OPT_WRITE_TIMEOUT"_L1,   MYSQL_OPT_WRITE_TIMEOUT,   setOptionInt},
        {"MYSQL_OPT_RECONNECT"_L1,       MYSQL_OPT_RECONNECT,       setOptionBool},
        {"MYSQL_OPT_LOCAL_INFILE"_L1,    MYSQL_OPT_LOCAL_INFILE,    setOptionInt},
        {"MYSQL_OPT_PROTOCOL"_L1,        MYSQL_OPT_PROTOCOL,        setOptionProtocol},
        {"MYSQL_SHARED_MEMORY_BASE_NAME"_L1, MYSQL_SHARED_MEMORY_BASE_NAME, setOptionString},
    };
    auto trySetOption = [&](const QStringView &key, const QStringView &value) -> bool {
      for (const mysqloptions &opt : options) {
          if (key == opt.key) {
              if (!opt.func(d->mysql, opt.option, value)) {
                  qCWarning(lcMysql, "QMYSQLDriver::open: Could not set connect option value "
                                     "'%ls' to '%ls'",
                            qUtf16Printable(QString(key)), qUtf16Printable(QString(value)));
              }
              return true;
          }
      }
      return false;
    };

    /* This is a hack to get MySQL's stored procedure support working.
       Since a stored procedure _may_ return multiple result sets,
       we have to enable CLIEN_MULTI_STATEMENTS here, otherwise _any_
       stored procedure call will fail.
    */
    unsigned int optionFlags = CLIENT_MULTI_STATEMENTS;
    const QList<QStringView> opts(QStringView(connOpts).split(u';', Qt::SkipEmptyParts));
    QString unixSocket;

    // extract the real options from the string
    for (const auto &option : opts) {
        const QStringView sv = QStringView(option).trimmed();
        qsizetype idx;
        if ((idx = sv.indexOf(u'=')) != -1) {
            const QStringView key = sv.left(idx).trimmed();
            const QStringView val = sv.mid(idx + 1).trimmed();
            if (trySetOption(key, val))
                continue;
            else if (key  == "UNIX_SOCKET"_L1)
                unixSocket = val.toString();
            else if (val == "TRUE"_L1 || val == "1"_L1)
                setOptionFlag(optionFlags, key);
            else
                qCWarning(lcMysql, "QMYSQLDriver::open: Illegal connect option value '%ls'",
                          qUtf16Printable(QString(sv)));
        } else {
            setOptionFlag(optionFlags, sv);
        }
    }

    // try utf8 with non BMP first, utf8 (BMP only) if that fails
    static const char wanted_charsets[][8] = { "utf8mb4", "utf8" };
#ifdef MARIADB_VERSION_ID
    MARIADB_CHARSET_INFO *cs = nullptr;
    for (const char *p : wanted_charsets) {
        cs = mariadb_get_charset_by_name(p);
        if (cs) {
            d->mysql->charset = cs;
            break;
        }
    }
#else
    // dummy
    struct {
        const char *csname;
    } *cs = nullptr;
#endif

    MYSQL *mysql = mysql_real_connect(d->mysql,
                                      host.isNull() ? nullptr : host.toUtf8().constData(),
                                      user.isNull() ? nullptr : user.toUtf8().constData(),
                                      password.isNull() ? nullptr : password.toUtf8().constData(),
                                      db.isNull() ? nullptr : db.toUtf8().constData(),
                                      (port > -1) ? port : 0,
                                      unixSocket.isNull() ? nullptr : unixSocket.toUtf8().constData(),
                                      optionFlags);

    if (mysql != d->mysql) {
        setLastError(qMakeError(tr("Unable to connect"),
                     QSqlError::ConnectionError, d));
        mysql_close(d->mysql);
        d->mysql = nullptr;
        setOpenError(true);
        return false;
    }

    // now ask the server to match the charset we selected
    if (!cs || mysql_set_character_set(d->mysql, cs->csname) != 0) {
        bool ok = false;
        for (const char *p : wanted_charsets) {
            if (mysql_set_character_set(d->mysql, p) == 0) {
                ok = true;
                break;
            }
        }
        if (!ok)
            qCWarning(lcMysql, "MySQL: Unable to set the client character set to utf8 (\"%s\"). "
                               "Using '%s' instead.",
                      mysql_error(d->mysql),
                      mysql_character_set_name(d->mysql));
    }

    if (!db.isEmpty() && mysql_select_db(d->mysql, db.toUtf8().constData())) {
        setLastError(qMakeError(tr("Unable to open database '%1'").arg(db), QSqlError::ConnectionError, d));
        mysql_close(d->mysql);
        setOpenError(true);
        return false;
    }

    d->preparedQuerysEnabled = checkPreparedQueries(d->mysql);
    d->dbName = db;

    if (d->preparedQuerysEnabled)
        setUtcTimeZone(d->mysql);

#if QT_CONFIG(thread)
    mysql_thread_init();
#endif

    setOpen(true);
    setOpenError(false);
    return true;
}

void QMYSQLDriver::close()
{
    Q_D(QMYSQLDriver);
    if (isOpen()) {
#if QT_CONFIG(thread)
        mysql_thread_end();
#endif
        mysql_close(d->mysql);
        d->mysql = nullptr;
        d->dbName.clear();
        setOpen(false);
        setOpenError(false);
    }
}

QSqlResult *QMYSQLDriver::createResult() const
{
    return new QMYSQLResult(this);
}

QStringList QMYSQLDriver::tables(QSql::TableType type) const
{
    Q_D(const QMYSQLDriver);
    QStringList tl;
    QSqlQuery q(createResult());
    if (type & QSql::Tables) {
        QString sql = "select table_name from information_schema.tables where table_schema = '"_L1 + d->dbName + "' and table_type = 'BASE TABLE'"_L1;
        q.exec(sql);

        while (q.next())
            tl.append(q.value(0).toString());
    }
    if (type & QSql::Views) {
        QString sql = "select table_name from information_schema.tables where table_schema = '"_L1 + d->dbName + "' and table_type = 'VIEW'"_L1;
        q.exec(sql);

        while (q.next())
            tl.append(q.value(0).toString());
    }
    return tl;
}

QSqlIndex QMYSQLDriver::primaryIndex(const QString &tablename) const
{
    QSqlIndex idx;
    if (!isOpen())
        return idx;

    QSqlQuery i(createResult());
    QString stmt("show index from %1;"_L1);
    QSqlRecord fil = record(tablename);
    i.exec(stmt.arg(escapeIdentifier(tablename, QSqlDriver::TableName)));
    while (i.isActive() && i.next()) {
        if (i.value(2).toString() == "PRIMARY"_L1) {
            idx.append(fil.field(i.value(4).toString()));
            idx.setCursorName(i.value(0).toString());
            idx.setName(i.value(2).toString());
        }
    }

    return idx;
}

QSqlRecord QMYSQLDriver::record(const QString &tablename) const
{
    Q_D(const QMYSQLDriver);
    if (!isOpen())
        return {};
    QSqlQuery i(createResult());
    QString stmt("SELECT * FROM %1 LIMIT 0"_L1);
    i.exec(stmt.arg(escapeIdentifier(tablename, QSqlDriver::TableName)));
    auto r = i.record();
    if (r.isEmpty())
        return r;
    // no binding of WHERE possible with MySQL
    // escaping on WHERE clause does not work, so use mysql_real_escape_string()
    stmt = "SELECT column_name, column_default FROM information_schema.columns WHERE table_schema = '"_L1
            + d->dbName + "' AND table_name = '%1'"_L1;
    const auto baTableName = tablename.toUtf8();
    QVarLengthArray<char> tableNameQuoted(baTableName.size() * 2 + 1);
#if defined(MARIADB_VERSION_ID)
    const auto len = mysql_real_escape_string(d->mysql, tableNameQuoted.data(),
                                              baTableName.data(), baTableName.size());
#else
    const auto len = mysql_real_escape_string_quote(d->mysql, tableNameQuoted.data(),
                                                    baTableName.data(), baTableName.size(), '\'');
#endif
    if (i.exec(stmt.arg(QString::fromUtf8(tableNameQuoted.data(), len)))) {
        while (i.next()) {
            const auto colName = i.value(0).toString();
            const auto recordIdx = r.indexOf(colName);
            if (recordIdx >= 0) {
                auto field = r.field(recordIdx);
                field.setDefaultValue(i.value(1));
                r.replace(recordIdx, field);
            }
        }
    }
    return r;
}

QVariant QMYSQLDriver::handle() const
{
    Q_D(const QMYSQLDriver);
    return QVariant::fromValue(d->mysql);
}

bool QMYSQLDriver::beginTransaction()
{
    Q_D(QMYSQLDriver);
    if (!isOpen()) {
        qCWarning(lcMysql, "QMYSQLDriver::beginTransaction: Database not open");
        return false;
    }
    if (mysql_query(d->mysql, "BEGIN WORK")) {
        setLastError(qMakeError(tr("Unable to begin transaction"),
                                QSqlError::StatementError, d));
        return false;
    }
    return true;
}

bool QMYSQLDriver::commitTransaction()
{
    Q_D(QMYSQLDriver);
    if (!isOpen()) {
        qCWarning(lcMysql, "QMYSQLDriver::commitTransaction: Database not open");
        return false;
    }
    if (mysql_query(d->mysql, "COMMIT")) {
        setLastError(qMakeError(tr("Unable to commit transaction"),
                                QSqlError::StatementError, d));
        return false;
    }
    return true;
}

bool QMYSQLDriver::rollbackTransaction()
{
    Q_D(QMYSQLDriver);
    if (!isOpen()) {
        qCWarning(lcMysql, "QMYSQLDriver::rollbackTransaction: Database not open");
        return false;
    }
    if (mysql_query(d->mysql, "ROLLBACK")) {
        setLastError(qMakeError(tr("Unable to rollback transaction"),
                                QSqlError::StatementError, d));
        return false;
    }
    return true;
}

QString QMYSQLDriver::formatValue(const QSqlField &field, bool trimStrings) const
{
    Q_D(const QMYSQLDriver);
    QString r;
    if (field.isNull()) {
        r = QStringLiteral("NULL");
    } else {
        switch (field.metaType().id()) {
        case QMetaType::Double:
            r = QString::number(field.value().toDouble(), 'g', field.precision());
            break;
        case QMetaType::QString:
            // Escape '\' characters
            r = QSqlDriver::formatValue(field, trimStrings);
            r.replace("\\"_L1, "\\\\"_L1);
            break;
        case QMetaType::QByteArray:
            if (isOpen()) {
                const QByteArray ba = field.value().toByteArray();
                // buffer has to be at least length*2+1 bytes
                QVarLengthArray<char, 512> buffer(ba.size() * 2 + 1);
                auto escapedSize = mysql_real_escape_string(d->mysql, buffer.data(), ba.data(), ba.size());
                r.reserve(escapedSize + 3);
                r = u'\'' + QString::fromUtf8(buffer.data(), escapedSize) + u'\'';
                break;
            } else {
                qCWarning(lcMysql, "QMYSQLDriver::formatValue: Database not open");
            }
            Q_FALLTHROUGH();
        case QMetaType::QDateTime:
            if (QDateTime dt = field.value().toDateTime(); dt.isValid()) {
                // MySQL format doesn't like the "Z" at the end, but does allow
                // "+00:00" starting in version 8.0.19. However, if we got here,
                // it's because the MySQL server is too old for prepared queries
                // in the first place, so it won't understand timezones either.
                r = u'\'' +
                        dt.date().toString(Qt::ISODate) +
                        u'T' +
                        dt.time().toString(Qt::ISODate) +
                        u'\'';
            }
            break;
        default:
            r = QSqlDriver::formatValue(field, trimStrings);
        }
    }
    return r;
}

QString QMYSQLDriver::escapeIdentifier(const QString &identifier, IdentifierType) const
{
    QString res = identifier;
    if (!identifier.isEmpty() && !identifier.startsWith(u'`') && !identifier.endsWith(u'`')) {
        res.replace(u'.', "`.`"_L1);
        res = u'`' + res + u'`';
    }
    return res;
}

bool QMYSQLDriver::isIdentifierEscaped(const QString &identifier, IdentifierType type) const
{
    Q_UNUSED(type);
    return identifier.size() > 2
        && identifier.startsWith(u'`') //left delimited
        && identifier.endsWith(u'`'); //right delimited
}

QT_END_NAMESPACE

#include "moc_qsql_mysql_p.cpp"
