Support Option<Vec> and Option<String> #14
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src/rust_option.rs
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| const _: () = { | ||
| impl_option_ffi! { <T: OptionPtrTarget>, usize, &'static () } |
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Here I define the partner struct (what was RustOption). So that I don't need a unique name for each different type, the definition is tucked away in a const. This means that we can't name this type outside of this block. The rest of the commit is removing all references to RustOption outside and replacing it with <Option<T> as OptionFfi>::Target to deal with this
| ) = &sig.ret | ||
| { | ||
| write!(out, ")"); | ||
| if let Some(ret) = &sig.ret { |
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This is starting to look like it wants to be a match instead of if-let chain
src/rust_option.rs
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| } | ||
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| /// SAFETY: ptr must be valid for 'a | ||
| pub unsafe fn from_raw_double_repr( |
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repr is for *RustVec<T> -> Option<&Vec<T>> and double_repr is specifically for *RustVec<RustString> -> Option<&Vec<String>> (both the container and the inner type change)
However, I can also just use as _ magic casts on the pointers to get rid of both the repr and double_repr methods (just from_raw) so I think I'm gonna do that instead
Hrmm is_direct was referring to the fact that I think that the code was actually magically passing T* anyway due to calling convention so my code was luckily working. I removed the
Option<&str> is not yet implemented because it is a fat pointer. Planning on doing it in a future diff though |
kuecks
changed the title
The main issue with supporting these structs is that they are both 3 pointers wide, while the existing code relied on Option being precisely 1 pointer wide (and thus only worked for pointer types). To resolve this, this PR has 2 commits:
Instead of using a single RustOption type to represent the C++ binding, using traits I defined different structs for the FFI representation of Option depending on T. For the old pointer types like &T and Box this is the old RustOption, but this now allows me to define new types (with a different size) to use for Option and Option
Actually implement Option and Option using the indirection above