Awaiting with context object. #115
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Hi Jonah, adding the context to .then() makes sense, but I think it's not as simple as it sounds: QCoro::Task<int> task = gimmeTask();
const auto result = co_await task.then(someObject, [someObject](int result) {
return someObject->magicalNumber() + result;
});If One option would be to join this with the #107 and allow context object only on |
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That seems like a good idea! |
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In some cases, one might want to update an object (for example a model), when a coroutine finished.
This can be done by either using a lambda that captures
thisas a coroutine, or by adding a coroutine member function.However there is no guarantee that once the coroutine finishes, the object still exists, so this can lead to crashes.
It is pretty much the same issue as the 3-arg connect in Qt: https://github.com/KDE/clazy/blob/master/docs/checks/README-connect-3arg-lambda.md
Is this already a solved problem in some way that I have missed?
If not, I propose adding an overload of
QCoro::Task<T>::thenthat takes aQObjectpointer as an additional argument, so that it can connect toQObject::destroyedof the context object, and not invoke the continuation if the signal has been emitted in the meantime.I currently can't find a good way to fix this when using the
co_awaitkeyword, but as this mostly concerns the issue of interaction between coroutine code and sync code, support in .then is probably enough.If needed, there could be something like
to inject the context even though using
co_await.I already have code for some of the proposed things here, so I can work on implementing it if needed.
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