Return T as opposed to &T on remove

[ccollie]

I'm storing a struct which is relatively "heavy", but in certain situations I need the capability to swap elements between indexes. Remove current returns &T when I need T, so I need to do a .clone() on the returned value.

Perhaps it's possible to add a swap() method ?

[ibraheemdev]

The reason papaya returns T is because there may be readers that still have access to the value being removed. It may be possible to add a remove_blocking method that waits for all readers to stop accessing a given value, but this may be more expensive than expected as memory reclamation is performed in batches. You could also implement this yourself with a one shot channel and a custom Drop implementation.

There's also no hardware instruction for swapping two atomic pointers, so a swap method would require locks or a complex atomic algorithm that I'm not sure is worth it.

If the clone is very expensive for you your only alternative is unfortunately fine-grained locking on each value.