75 lines
2.0 KiB
Rust
75 lines
2.0 KiB
Rust
use dyn_any::StaticType;
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use dyn_clone::DynClone;
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use dyn_any::{DynAny, Upcast};
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pub type Value = Box<dyn ValueTrait>;
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pub trait ValueTrait: DynAny<'static> + Upcast<dyn DynAny<'static>> + std::fmt::Debug + DynClone {}
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pub trait IntoValue: Sized + ValueTrait + 'static {
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fn into_any(self) -> Value {
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Box::new(self)
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}
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}
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impl<T: 'static + StaticType + Upcast<dyn DynAny<'static>> + std::fmt::Debug + PartialEq + Clone> ValueTrait for T {}
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impl<T: 'static + ValueTrait> IntoValue for T {}
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#[repr(C)]
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pub(crate) struct Vtable {
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pub(crate) destructor: unsafe fn(*mut ()),
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pub(crate) size: usize,
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pub(crate) align: usize,
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}
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#[repr(C)]
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pub(crate) struct TraitObject {
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pub(crate) self_ptr: *mut u8,
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pub(crate) vtable: &'static Vtable,
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}
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impl PartialEq for Box<dyn ValueTrait> {
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#[cfg_attr(miri, ignore)]
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fn eq(&self, other: &Self) -> bool {
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if self.type_id() != other.type_id() {
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return false;
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}
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let self_trait_object = unsafe { std::mem::transmute::<&dyn ValueTrait, TraitObject>(self.as_ref()) };
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let other_trait_object = unsafe { std::mem::transmute::<&dyn ValueTrait, TraitObject>(other.as_ref()) };
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let size = self_trait_object.vtable.size;
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let self_mem = unsafe { std::slice::from_raw_parts(self_trait_object.self_ptr, size) };
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let other_mem = unsafe { std::slice::from_raw_parts(other_trait_object.self_ptr, size) };
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self_mem == other_mem
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}
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}
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impl Clone for Value {
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fn clone(&self) -> Self {
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let self_trait_object = unsafe { std::mem::transmute::<&dyn ValueTrait, TraitObject>(self.as_ref()) };
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let size = self_trait_object.vtable.size;
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let self_mem = unsafe { std::slice::from_raw_parts(self_trait_object.self_ptr, size) }.to_owned();
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let ptr = Vec::leak(self_mem);
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unsafe {
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std::mem::transmute(TraitObject {
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self_ptr: ptr as *mut [u8] as *mut u8,
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vtable: self_trait_object.vtable,
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})
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}
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test_any_src() {
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assert!(2_u32.into_any() == 2_u32.into_any());
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assert!(2_u32.into_any() != 3_u32.into_any());
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assert!(2_u32.into_any() != 3_i32.into_any());
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}
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}
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