 c27a3cff6d
			
		
	
	
		c27a3cff6d
		
	
	
	
	
		
			
			# Objective Currently, `Reflect` is unsafe to implement because of a contract in which `any` and `any_mut` must return `self`, or `downcast` will cause UB. This PR makes `Reflect` safe, makes `downcast` not use unsafe, and eliminates this contract. ## Solution This PR adds a method to `Reflect`, `any`. It also renames the old `any` to `as_any`. `any` now takes a `Box<Self>` and returns a `Box<dyn Any>`. --- ## Changelog ### Added: - `any()` method - `represents()` method ### Changed: - `Reflect` is now a safe trait - `downcast()` is now safe - The old `any` is now called `as_any`, and `any_mut` is now `as_mut_any` ## Migration Guide - Reflect derives should not have to change anything - Manual reflect impls will need to remove the `unsafe` keyword, add `any()` implementations, and rename the old `any` and `any_mut` to `as_any` and `as_mut_any`. - Calls to `any`/`any_mut` must be changed to `as_any`/`as_mut_any` ## Points of discussion: - Should renaming `any` be avoided and instead name the new method `any_box`? - ~~Could there be a performance regression from avoiding the unsafe? I doubt it, but this change does seem to introduce redundant checks.~~ - ~~Could/should `is` and `type_id()` be implemented differently? For example, moving `is` onto `Reflect` as an `fn(&self, TypeId) -> bool`~~ Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
		
			
				
	
	
		
			142 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			142 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
| use smallvec::SmallVec;
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| use std::any::Any;
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| 
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| use crate::utility::GenericTypeInfoCell;
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| use crate::{
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|     Array, ArrayIter, FromReflect, List, ListInfo, Reflect, ReflectMut, ReflectRef, TypeInfo, Typed,
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| };
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| 
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| impl<T: smallvec::Array + Send + Sync + 'static> Array for SmallVec<T>
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| where
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|     T::Item: FromReflect + Clone,
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| {
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|     fn get(&self, index: usize) -> Option<&dyn Reflect> {
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|         if index < SmallVec::len(self) {
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|             Some(&self[index] as &dyn Reflect)
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|         } else {
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|             None
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|         }
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|     }
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| 
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|     fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {
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|         if index < SmallVec::len(self) {
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|             Some(&mut self[index] as &mut dyn Reflect)
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|         } else {
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|             None
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|         }
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|     }
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| 
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|     fn len(&self) -> usize {
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|         <SmallVec<T>>::len(self)
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|     }
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| 
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|     fn iter(&self) -> ArrayIter {
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|         ArrayIter {
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|             array: self,
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|             index: 0,
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|         }
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|     }
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| }
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| 
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| impl<T: smallvec::Array + Send + Sync + 'static> List for SmallVec<T>
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| where
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|     T::Item: FromReflect + Clone,
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| {
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|     fn push(&mut self, value: Box<dyn Reflect>) {
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|         let value = value.take::<T::Item>().unwrap_or_else(|value| {
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|             <T as smallvec::Array>::Item::from_reflect(&*value).unwrap_or_else(|| {
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|                 panic!(
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|                     "Attempted to push invalid value of type {}.",
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|                     value.type_name()
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|                 )
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|             })
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|         });
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|         SmallVec::push(self, value);
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|     }
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| }
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| 
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| impl<T: smallvec::Array + Send + Sync + 'static> Reflect for SmallVec<T>
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| where
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|     T::Item: FromReflect + Clone,
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| {
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|     fn type_name(&self) -> &str {
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|         std::any::type_name::<Self>()
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|     }
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| 
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|     fn get_type_info(&self) -> &'static TypeInfo {
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|         <Self as Typed>::type_info()
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|     }
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| 
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|     fn into_any(self: Box<Self>) -> Box<dyn Any> {
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|         self
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|     }
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| 
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|     fn as_any(&self) -> &dyn Any {
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|         self
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|     }
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| 
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|     fn as_any_mut(&mut self) -> &mut dyn Any {
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|         self
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|     }
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| 
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|     fn as_reflect(&self) -> &dyn Reflect {
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|         self
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|     }
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| 
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|     fn as_reflect_mut(&mut self) -> &mut dyn Reflect {
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|         self
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|     }
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| 
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|     fn apply(&mut self, value: &dyn Reflect) {
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|         crate::list_apply(self, value);
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|     }
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| 
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|     fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>> {
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|         *self = value.take()?;
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|         Ok(())
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|     }
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| 
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|     fn reflect_ref(&self) -> ReflectRef {
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|         ReflectRef::List(self)
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|     }
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| 
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|     fn reflect_mut(&mut self) -> ReflectMut {
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|         ReflectMut::List(self)
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|     }
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| 
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|     fn clone_value(&self) -> Box<dyn Reflect> {
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|         Box::new(List::clone_dynamic(self))
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|     }
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| 
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|     fn reflect_partial_eq(&self, value: &dyn Reflect) -> Option<bool> {
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|         crate::list_partial_eq(self, value)
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|     }
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| }
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| 
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| impl<T: smallvec::Array + Send + Sync + 'static> Typed for SmallVec<T>
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| where
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|     T::Item: FromReflect + Clone,
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| {
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|     fn type_info() -> &'static TypeInfo {
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|         static CELL: GenericTypeInfoCell = GenericTypeInfoCell::new();
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|         CELL.get_or_insert::<Self, _>(|| TypeInfo::List(ListInfo::new::<Self, T::Item>()))
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|     }
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| }
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| 
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| impl<T: smallvec::Array + Send + Sync + 'static> FromReflect for SmallVec<T>
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| where
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|     T::Item: FromReflect + Clone,
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| {
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|     fn from_reflect(reflect: &dyn Reflect) -> Option<Self> {
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|         if let ReflectRef::List(ref_list) = reflect.reflect_ref() {
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|             let mut new_list = Self::with_capacity(ref_list.len());
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|             for field in ref_list.iter() {
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|                 new_list.push(<T as smallvec::Array>::Item::from_reflect(field)?);
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|             }
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|             Some(new_list)
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|         } else {
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|             None
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|         }
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|     }
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| }
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