Use ffigen for C-API bindings

[vaind]

Part of dart-archive/ffigen#139 - switches from manual binding definitions to ffigen generated code

[vaind]

@greenrobot-team you can have a first look when it works for you. Tests crash at the moment but I don't expect many changes to get it fixed.

[greenrobot-team]

Won't be able to complete my review until I'm back. Anyhow, most of what I've seen of the first commit seems straight forward.

[Buggaboo]

You might want to check the size of the pointers. They should be machine word size, unless instructed differently to the compiler :/ Struct padding (I assume no packing is applied) could also be an issue.

Really cool tool. I didn't know about it until now. I tried writing my own this summer. I guess I could throw that away now.

[vaind]

You might want to check the size of the pointers. They should be machine word size, unless instructed differently to the compiler :/

Thanks, I'm aware of that. I had to do some patching until it's resolved in ffigen

[greenrobot]

So many code changes... Maybe walk me quickly through it tomorrow; e.g. what's generated and what not...

Did you test this on a 32 bit system (in addition to 64 bit ofc); e.g. Android?

[greenrobot]

It's +10,112 −1,483 LoC and I assume the generated code is most of that. Can you give a high level explanation why it's almost +9K net? Maybe some example?

[greenrobot]

You might want to check the size of the pointers. They should be machine word size, unless instructed differently to the compiler :/

Thanks, I'm aware of that. I had to do some patching until it's resolved in ffigen

Could you point us to that patch you did?

[vaind]

It's +10,112 −1,483 LoC and I assume the generated code is most of that. Can you give a high level explanation why it's almost +9K net? Maybe some example?

Yes, most of it is the generated code, the (hopefully temporary) patch file & objectbox.h, 9777 lines added altogether.

The generated code is a lot larger then our manual code because it doesn't use templates (generics) which we used to reduce the amount of manual work (though it has made the code quite a bit less readable) and it is more type safe (all pointers now have types, like Pointer<OBX_Store> instead of the original Pointer<Void>. Also, it's actually complete (with the exception of obx_cursor_* which I've excluded for now (unused), as opposed to the original binding code where we've only defined what we needed.

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Could you point us to that patch you did?

https://github.com/objectbox/objectbox-dart/pull/146/files#diff-fdd27307bfa2cd39c097a0ca82b66dfce50d199482400073ea7b37399e74ff22

Did you test this on a 32 bit system (in addition to 64 bit ofc); e.g. Android?

Yes, tested the example app on the 32-bit android. We can't run our complete test-suite on device yet.