Attaching signals and slots to an object within a QSharedPointer

Question

My application contained several functions like this:

void SomeClass::set_data_provider(DataProvider *data_provider)
{
    connect(data_provider, SIGNAL(data_ava         


        

Answer 1

For completeness, here is an extension of @hank’s answer. I provide six connect-like functions:

• connect_from_pointer takes a QSharedPointer as its first argument and the usual QObject * as its third argument.
• connect_to_pointer takes the usual QObject * as its first argument and a QSharedPointer as its third argument.
• connect_pointers takes QSharedPointers for both parameters.

There are two versions of each of these: one that accepts the SIGNAL()/SLOT() syntax and one that accepts the (recommended) function pointers.

These are syntactically atrocious, but that’s templates for you.

template
QMetaObject::Connection connect_from_pointer(
    const QSharedPointer& sender,
    const char *signal,
    const QObject *receiver,
    const char *method,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender.data(), signal, receiver, method, type);
}

template 
QMetaObject::Connection connect_from_pointer(
    const QSharedPointer::Object>& sender,
    Func1 signal,
    const typename QtPrivate::FunctionPointer::Object *receiver,
    Func2 slot,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender.data(), signal, receiver, slot, type);
}

template
QMetaObject::Connection connect_to_pointer(
    const QObject *sender,
    const char *signal,
    const QSharedPointer& receiver,
    const char *method,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender, signal, receiver.data(), method, type);
}

template 
QMetaObject::Connection connect_to_pointer(
    const typename QtPrivate::FunctionPointer::Object *sender,
    Func1 signal,
    const QSharedPointer::Object>& receiver,
    Func2 slot,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender, signal, receiver.data(), slot, type);
}

template
QMetaObject::Connection connect_pointers(
    const QSharedPointer& sender,
    const char *signal,
    const QSharedPointer& receiver,
    const char *method,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender.data(), signal, receiver.data(), method, type);
}

template 
QMetaObject::Connection connect_pointers(
    const QSharedPointer::Object>& sender,
    Func1 signal,
    const QSharedPointer::Object>& receiver,
    Func2 slot,
    Qt::ConnectionType type = Qt::AutoConnection)
{
    return QObject::connect(sender.data(), signal, receiver.data(), slot, type);
}