qt5base-lts/tests/auto/qscopedvaluerollback/tst_qscopedvaluerollback.cpp

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#include <QtTest/QtTest>
#include <QtCore/QScopedValueRollback>

/*!
 \class tst_QScopedValueRollback
 \internal
 \since 4.8
 \brief Tests class QScopedValueRollback.

 */
class tst_QScopedValueRollback : public QObject
{
    Q_OBJECT

private Q_SLOTS:
    void leavingScope();
    void leavingScopeAfterCommit();
    void rollbackToPreviousCommit();
    void exceptions();
    void earlyExitScope();
private:
    void earlyExitScope_helper(int exitpoint, int &member);
};

void tst_QScopedValueRollback::leavingScope()
{
    int i = 0;
    bool b = false;
    QString s("This is useful");

    //test rollback on going out of scope
    {
        QScopedValueRollback<int> ri(i);
        QScopedValueRollback<bool> rb(b);
        QScopedValueRollback<QString> rs(s);
        QCOMPARE(b, false);
        QCOMPARE(i, 0);
        QCOMPARE(s, QString("This is useful"));
        b = true;
        i = 1;
        s = "Useless";
        QCOMPARE(b, true);
        QCOMPARE(i, 1);
        QCOMPARE(s, QString("Useless"));
    }
    QCOMPARE(b, false);
    QCOMPARE(i, 0);
    QCOMPARE(s, QString("This is useful"));
}

void tst_QScopedValueRollback::leavingScopeAfterCommit()
{
    int i = 0;
    bool b = false;
    QString s("This is useful");

    //test rollback on going out of scope
    {
        QScopedValueRollback<int> ri(i);
        QScopedValueRollback<bool> rb(b);
        QScopedValueRollback<QString> rs(s);
        QCOMPARE(b, false);
        QCOMPARE(i, 0);
        QCOMPARE(s, QString("This is useful"));
        b = true;
        i = 1;
        s = "Useless";
        QCOMPARE(b, true);
        QCOMPARE(i, 1);
        QCOMPARE(s, QString("Useless"));
        ri.commit();
        rb.commit();
        rs.commit();
    }
    QCOMPARE(b, true);
    QCOMPARE(i, 1);
    QCOMPARE(s, QString("Useless"));
}

void tst_QScopedValueRollback::rollbackToPreviousCommit()
{
    int i=0;
    {
        QScopedValueRollback<int> ri(i);
        i++;
        ri.commit();
        i++;
    }
    QCOMPARE(i,1);
    {
        QScopedValueRollback<int> ri1(i);
        i++;
        ri1.commit();
        i++;
        ri1.commit();
        i++;
    }
    QCOMPARE(i,3);
}

void tst_QScopedValueRollback::exceptions()
{
    bool b = false;
    bool caught = false;
    QT_TRY
    {
        QScopedValueRollback<bool> rb(b);
        b = true;
        QT_THROW(std::bad_alloc()); //if Qt compiled without exceptions this is noop
        rb.commit(); //if Qt compiled without exceptions, true is committed
    }
    QT_CATCH(...)
    {
        caught = true;
    }
    QCOMPARE(b, !caught); //expect false if exception was thrown, true otherwise
}

void tst_QScopedValueRollback::earlyExitScope()
{
    int i=0;
    int j=0;
    while (true) {
        QScopedValueRollback<int> ri(i);
        i++;
        j=i;
        if (i>8) break;
        ri.commit();
    }
    QCOMPARE(i,8);
    QCOMPARE(j,9);

    for (i = 0; i < 5; i++) {
        j=1;
        earlyExitScope_helper(i,j);
        QCOMPARE(j, 1<<i);
    }
}

void tst_QScopedValueRollback::earlyExitScope_helper(int exitpoint, int& member)
{
    QScopedValueRollback<int> r(member);
    member *= 2;
    if (exitpoint == 0)
        return;
    r.commit();
    member *= 2;
    if (exitpoint == 1)
        return;
    r.commit();
    member *= 2;
    if (exitpoint == 2)
        return;
    r.commit();
    member *= 2;
    if (exitpoint == 3)
        return;
    r.commit();
}

QTEST_MAIN(tst_QScopedValueRollback)
#include "tst_qscopedvaluerollback.moc"