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61 lines
1.5 KiB
Rust
61 lines
1.5 KiB
Rust
/// Implements the `IntoMultitrait` trait on the defined type.
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/// ```rust
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/// use multi_trait_object::*;
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/// struct MyStruct {
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/// a: u64,
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/// }
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///
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/// trait MyTrait {}
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/// trait MyOtherTrait {}
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///
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/// impl MyTrait for MyStruct{}
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/// impl MyOtherTrait for MyStruct {}
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///
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/// impl_trait_object!(MyStruct, dyn MyTrait, dyn MyOtherTrait);
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/// ```
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#[macro_export]
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macro_rules! impl_trait_object {
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($obj:ty, $($trt:ty),*) => {
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impl $crate::IntoMultitrait for $obj {
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fn into_multitrait(self) -> $crate::MultitraitObject {
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let mut mto = $crate::MultitraitObject::new(self);
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$(
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$crate::register_traits!(mto, $obj, $trt);
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)*
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mto
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}
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}
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}
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}
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/// Registers multiple trait_impl on a multitrait object
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/// ```rust
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/// use multi_trait_object::*;
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/// use std::fmt::{Debug, Display};
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///
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/// let value = String::new();
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/// let mut mto = MultitraitObject::new(value);
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/// register_traits!(mto, String, dyn Debug, dyn Display);
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/// ```
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#[macro_export]
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macro_rules! register_traits {
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($r:expr, $v:ty, $($t:ty), +) => {
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$(
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$r._register::<$t>($crate::__fat_pointer!($v as $t).vptr);
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)+
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}
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}
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#[doc(hidden)]
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#[macro_export]
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macro_rules! __fat_pointer {
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($v:ty as $t:ty) => {{
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let x = ::std::ptr::null::<$v>() as *const $v as *const $t;
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#[allow(unused_unsafe)]
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unsafe {
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std::mem::transmute::<_, $crate::FatPointer>(x)
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}
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}}
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}
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