I will look at your managed approach to understand it better.
One drawback I can think of is that destruction might not occur
immediately. This can be an issue for shared libraries when the
GC hasn't run when the library call returns to the host
application.
Maybe it's a C++ bias, but the RefCounted approach seems like
such a natural fit for this use case and so far it's working
well. There is the race condition issue but I think there is an
allocator solution for that coming.
erik
On Wednesday, 2 March 2016 at 04:11:10 UTC, Rikki Cattermole
wrote:
On 02/03/16 4:48 PM, Erik Smith wrote:
Yes agree that the poly Database is broken - it isn't
reference counted
and I will fix that.
My point was, you shouldn't handle that.
Your sample code had me wondering if I am missing something
else, but I
can't see another issue yet. I think the use of classes would
definitely lead to problems with resources being freed out of
order or
too late.
Currently its use after free. E.g. destructor gets called but
there is still a copy around.
At the very least it should be an explicit call.
If classes lead to problems, so will structs.
As far as memory management options, my plan is to work
allocators into
the design and that would seem to provide a lot of options.
I'm having
a problem at the moment with MallocAllocator's shared
interface. I'm
not sure why it's shared since malloc/free are thread safe and
I can't
seem to cast away the shared. I'm sure there is a reason.
Use IAllocator. Don't touch the structs unless you want pain.
Oh and btw final class is your friend.
As an FYI here is my managed memory concept
https://github.com/rikkimax/alphaPhobos/blob/master/source/std/experimental/memory/managed.d its not finished but it mostly works.
Of course I would want to go the more OOP way, sure thats more
allocations but over all I think there are enough wins that its
worth it. So if you feel it doesn't fit well with your goal,
say so :)
erik
On Wednesday, 2 March 2016 at 03:07:54 UTC, Rikki Cattermole
wrote:
Okay I've found a problem.
Here is some code demonstrating it.
http://dpaste.dzfl.pl/022c9e610a18
Now take a look again at Database
https://github.com/cruisercoder/dstddb/blob/master/src/std/database/poly/database.d#L37
Do you see the problem?
The solution is simple.
The client database type can be a struct or a class. It
doesn't matter
too much (assuming you're going the way of ranges).
But the intermediary representation must be on the heap and
should
probably use the constructor and not a static create method
to get it.
This way people can use other memory management solutions and
construct it however they like.
