Add HandlerFuncType trait #439
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src/structures/idt.rs
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| /// This method is only usable with the `abi_x86_interrupt` feature enabled. Without it, the | ||
| /// unsafe [`Entry::set_handler_addr`] method has to be used instead. | ||
| #[inline] | ||
| pub fn set_handler_fn(&mut self, handler: &F) -> &mut EntryOptions { |
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For backwards compatibility, set_handler_fn needs to take the handler by value, not by reference.
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Gotcha. I didn't realize that function pointers are Copy, so it doesn't matter if it's owned or not
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Just for my own understanding (I'm fairly new to Rust), why does set_handler_fn take the handler function by value? If there's nothing in set_handler_fn that requires the function to be moved, isn't it better to take a reference so that the caller can keep using the argument? Or is it specifically because it's a function, there's never a reason to pass a function by reference, and you should always Copy as needed?
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Ya this can be a confusing thing initially, especially because the function Traits (Fn, FnMut, FnOnce) are often handled differently.
A type like fn(u8) -> u8 or extern "x86-interrupt" fn(InterruptStackFrame) -> ! is a function pointer, so it references a specific function. It this way, it is similar to &T or *const T in that it is:
- pointer sized
- a shared reference to something immutable.
So for the same reason we usually don't use &&T or &*const T, using &fn(u8) -> u8 is uncommon.
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@josephlr how's that? |
Signed-off-by: Joe Richey <joerichey@google.com>
Fixes #438