implement `locate_handle_buffer` function?

[AtsukiTak]

Hi there!

It seems that BootServices does not implement locate_handle_buffer function. Is there any reason to not do it?

I just tried and found that making a tidy API is not easy. (My API is like below)

pub fn locate_handle_buffer(&self, search_ty: SearchType) -> Result<(*mut Handle, usize)>

But it seems to work correctly. So if it is the only reason to not do, I would like to discuss API :) Thanks!

[nicholasbishop]

It seems that BootServices does not implement locate_handle_buffer function. Is there any reason to not do it?

No reason, just hasn't been done yet. Thanks for looking into it :)

I think a good model to look at for implementing this is protocols_per_handle. That shows an example of wrapping the pointer into a slice, and also ensuring that the memory is freed on drop.

[AtsukiTak]

Thanks for the quick reply!

I think a good model to look at for implementing this is protocols_per_handle. That shows an example of wrapping the pointer into a slice, and also ensuring that the memory is freed on drop.

Yes, actually, that was the first design I tried. But the problem is that Handle is a pointer and implement Clone. So if someone clones Handle and then we free that pointer, it will cause UB.

Wait... maybe it's not true.

The memory allocated by the locate_handle_buffer function is not a Handle pointer itself. It is a buffer that contains Handle pointers. So we can free that buffer safely on drop. Is it right?

[AtsukiTak]

Before I will try to implement locate_handle_buffer, I would like to fix #374

[nicholasbishop]

The memory allocated by the locate_handle_buffer function is not a Handle pointer itself. It is a buffer that contains Handle pointers. So we can free that buffer safely on drop. Is it right?

That's correct, it should be safe to free the buffer containing Handle pointers.