qsqldriver.cpp

Go to the documentation of this file.

/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtSql module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qsqldriver.h"

#include "qdatetime.h"
#include "qsqlerror.h"
#include "qsqlfield.h"
#include "qsqlindex.h"
#include "private/qobject_p.h"

QT_BEGIN_NAMESPACE

static QString prepareIdentifier(const QString &identifier,
        QSqlDriver::IdentifierType type, const QSqlDriver *driver)
{
    Q_ASSERT( driver != NULL );
    QString ret = identifier;
    if (!driver->isIdentifierEscaped(identifier, type)) {
        ret = driver->escapeIdentifier(identifier, type);
    }
    return ret;
}

class QSqlDriverPrivate : public QObjectPrivate
{
public:
    QSqlDriverPrivate();
    virtual ~QSqlDriverPrivate();

public:
    // @CHECK: this member is never used. It was named q, which expanded to q_func().
    QSqlDriver *q_func();
    uint isOpen : 1;
    uint isOpenError : 1;
    QSqlError error;
    QSql::NumericalPrecisionPolicy precisionPolicy;
};

inline QSqlDriverPrivate::QSqlDriverPrivate()
    : QObjectPrivate(), isOpen(false), isOpenError(false), precisionPolicy(QSql::LowPrecisionDouble)
{
}

QSqlDriverPrivate::~QSqlDriverPrivate()
{
}

QSqlDriver::QSqlDriver(QObject *parent)
    : QObject(*new QSqlDriverPrivate, parent)
{
}

QSqlDriver::~QSqlDriver()
{
}

bool QSqlDriver::isOpen() const
{
    return d_func()->isOpen;
}

bool QSqlDriver::isOpenError() const
{
    return d_func()->isOpenError;
}

void QSqlDriver::setOpen(bool open)
{
    d_func()->isOpen = open;
}

void QSqlDriver::setOpenError(bool error)
{
    d_func()->isOpenError = error;
    if (error)
        d_func()->isOpen = false;
}

bool QSqlDriver::beginTransaction()
{
    return false;
}

bool QSqlDriver::commitTransaction()
{
    return false;
}

bool QSqlDriver::rollbackTransaction()
{
    return false;
}

void QSqlDriver::setLastError(const QSqlError &error)
{
    d_func()->error = error;
}

QSqlError QSqlDriver::lastError() const
{
    return d_func()->error;
}

QStringList QSqlDriver::tables(QSql::TableType) const
{
    return QStringList();
}

QSqlIndex QSqlDriver::primaryIndex(const QString&) const
{
    return QSqlIndex();
}


QSqlRecord QSqlDriver::record(const QString & /* tableName */) const
{
    return QSqlRecord();
}

QString QSqlDriver::escapeIdentifier(const QString &identifier, IdentifierType) const
{
    return identifier;
}

bool QSqlDriver::isIdentifierEscaped(const QString &identifier, IdentifierType type) const
{
    bool result;
    QMetaObject::invokeMethod(const_cast<QSqlDriver*>(this),
                            "isIdentifierEscapedImplementation", Qt::DirectConnection,
                            Q_RETURN_ARG(bool, result),
                            Q_ARG(QString, identifier),
                            Q_ARG(IdentifierType, type));
    return result;
}

QString QSqlDriver::stripDelimiters(const QString &identifier, IdentifierType type) const
{
    QString result;
    QMetaObject::invokeMethod(const_cast<QSqlDriver*>(this),
                            "stripDelimitersImplementation", Qt::DirectConnection,
                            Q_RETURN_ARG(QString, result),
                            Q_ARG(QString, identifier),
                            Q_ARG(IdentifierType, type));
    return result;
}

QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName,
                                 const QSqlRecord &rec, bool preparedStatement) const
{
    int i;
    QString s;
    s.reserve(128);
    switch (type) {
    case SelectStatement:
        for (i = 0; i < rec.count(); ++i) {
            if (rec.isGenerated(i))
                s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(QLatin1String(", "));
        }
        if (s.isEmpty())
            return s;
        s.chop(2);
        s.prepend(QLatin1String("SELECT ")).append(QLatin1String(" FROM ")).append(tableName);
        break;
    case WhereStatement:
        if (preparedStatement) {
            for (int i = 0; i < rec.count(); ++i) {
                s.append(prepareIdentifier(rec.fieldName(i), FieldName,this));
                if (rec.isNull(i))
                    s.append(QLatin1String(" IS NULL"));
                else
                    s.append(QLatin1String(" = ?"));
                s.append(QLatin1String(" AND "));
            }
        } else {
            for (i = 0; i < rec.count(); ++i) {
                s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this));
                QString val = formatValue(rec.field(i));
                if (val == QLatin1String("NULL"))
                    s.append(QLatin1String(" IS NULL"));
                else
                    s.append(QLatin1String(" = ")).append(val);
                s.append(QLatin1String(" AND "));
            }
        }
        if (!s.isEmpty()) {
            s.prepend(QLatin1String("WHERE "));
            s.chop(5); // remove tailing AND
        }
        break;
    case UpdateStatement:
        s.append(QLatin1String("UPDATE ")).append(tableName).append(
                 QLatin1String(" SET "));
        for (i = 0; i < rec.count(); ++i) {
            if (!rec.isGenerated(i))
                continue;
            s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(QLatin1Char('='));
            if (preparedStatement)
                s.append(QLatin1Char('?'));
            else
                s.append(formatValue(rec.field(i)));
            s.append(QLatin1String(", "));
        }
        if (s.endsWith(QLatin1String(", ")))
            s.chop(2);
        else
            s.clear();
        break;
    case DeleteStatement:
        s.append(QLatin1String("DELETE FROM ")).append(tableName);
        break;
    case InsertStatement: {
        s.append(QLatin1String("INSERT INTO ")).append(tableName).append(QLatin1String(" ("));
        QString vals;
        for (i = 0; i < rec.count(); ++i) {
            if (!rec.isGenerated(i))
                continue;
            s.append(prepareIdentifier(rec.fieldName(i), QSqlDriver::FieldName, this)).append(QLatin1String(", "));
            if (preparedStatement)
                vals.append(QLatin1Char('?'));
            else
                vals.append(formatValue(rec.field(i)));
            vals.append(QLatin1String(", "));
        }
        if (vals.isEmpty()) {
            s.clear();
        } else {
            vals.chop(2); // remove trailing comma
            s[s.length() - 2] = QLatin1Char(')');
            s.append(QLatin1String("VALUES (")).append(vals).append(QLatin1Char(')'));
        }
        break; }
    }
    return s;
}

QString QSqlDriver::formatValue(const QSqlField &field, bool trimStrings) const
{
    const QLatin1String nullTxt("NULL");

    QString r;
    if (field.isNull())
        r = nullTxt;
    else {
        switch (field.type()) {
        case QVariant::Int:
        case QVariant::UInt:
            if (field.value().type() == QVariant::Bool)
                r = field.value().toBool() ? QLatin1String("1") : QLatin1String("0");
            else
                r = field.value().toString();
            break;
#ifndef QT_NO_DATESTRING
    case QVariant::Date:
            if (field.value().toDate().isValid())
                r = QLatin1Char('\'') + field.value().toDate().toString(Qt::ISODate)
                    + QLatin1Char('\'');
            else
                r = nullTxt;
            break;
        case QVariant::Time:
            if (field.value().toTime().isValid())
                r =  QLatin1Char('\'') + field.value().toTime().toString(Qt::ISODate)
                     + QLatin1Char('\'');
            else
                r = nullTxt;
            break;
        case QVariant::DateTime:
            if (field.value().toDateTime().isValid())
                r = QLatin1Char('\'') +
                    field.value().toDateTime().toString(Qt::ISODate) + QLatin1Char('\'');
            else
                r = nullTxt;
            break;
#endif
        case QVariant::String:
        case QVariant::Char:
        {
            QString result = field.value().toString();
            if (trimStrings) {
                int end = result.length();
                while (end && result.at(end-1).isSpace()) /* skip white space from end */
                    end--;
                result.truncate(end);
            }
            /* escape the "'" character */
            result.replace(QLatin1Char('\''), QLatin1String("''"));
            r = QLatin1Char('\'') + result + QLatin1Char('\'');
            break;
        }
        case QVariant::Bool:
            r = QString::number(field.value().toBool());
            break;
        case QVariant::ByteArray : {
            if (hasFeature(BLOB)) {
                QByteArray ba = field.value().toByteArray();
                QString res;
                static const char hexchars[] = "0123456789abcdef";
                for (int i = 0; i < ba.size(); ++i) {
                    uchar s = (uchar) ba[i];
                    res += QLatin1Char(hexchars[s >> 4]);
                    res += QLatin1Char(hexchars[s & 0x0f]);
                }
                r = QLatin1Char('\'') + res +  QLatin1Char('\'');
                break;
            }
        }
        default:
            r = field.value().toString();
            break;
        }
    }
    return r;
}

QVariant QSqlDriver::handle() const
{
    return QVariant();
}

bool QSqlDriver::subscribeToNotification(const QString &name)
{
    bool result;
    QMetaObject::invokeMethod(const_cast<QSqlDriver *>(this),
                  "subscribeToNotificationImplementation", Qt::DirectConnection,
                  Q_RETURN_ARG(bool, result),
                  Q_ARG(QString, name));
    return result;
}

bool QSqlDriver::unsubscribeFromNotification(const QString &name)
{
    bool result;
    QMetaObject::invokeMethod(const_cast<QSqlDriver *>(this),
                  "unsubscribeFromNotificationImplementation", Qt::DirectConnection,
                  Q_RETURN_ARG(bool, result),
                  Q_ARG(QString, name));
    return result;
}

QStringList QSqlDriver::subscribedToNotifications() const
{
    QStringList result;
    QMetaObject::invokeMethod(const_cast<QSqlDriver *>(this),
                  "subscribedToNotificationsImplementation", Qt::DirectConnection,
                  Q_RETURN_ARG(QStringList, result));
    return result;
}

bool QSqlDriver::subscribeToNotificationImplementation(const QString &name)
{
    Q_UNUSED(name);
    return false;
}

bool QSqlDriver::unsubscribeFromNotificationImplementation(const QString &name)
{
    Q_UNUSED(name);
    return false;
}

QStringList QSqlDriver::subscribedToNotificationsImplementation() const
{
    return QStringList();
}

bool QSqlDriver::isIdentifierEscapedImplementation(const QString &identifier, IdentifierType type) const
{
    Q_UNUSED(type);
    return identifier.size() > 2
        && identifier.startsWith(QLatin1Char('"')) //left delimited
        && identifier.endsWith(QLatin1Char('"')); //right delimited
}

QString QSqlDriver::stripDelimitersImplementation(const QString &identifier, IdentifierType type) const
{
    QString ret;
    if (this->isIdentifierEscaped(identifier, type)) {
        ret = identifier.mid(1);
        ret.chop(1);
    } else {
        ret = identifier;
    }
    return ret;
}

void QSqlDriver::setNumericalPrecisionPolicy(QSql::NumericalPrecisionPolicy precisionPolicy)
{
    d_func()->precisionPolicy = precisionPolicy;
}

QSql::NumericalPrecisionPolicy QSqlDriver::numericalPrecisionPolicy() const
{
    return d_func()->precisionPolicy;
}

QT_END_NAMESPACE