aabc47f290
# Objective We have some macros that are public but only used internally for now. They fail on user's code due to the use of crate names like `bevy_utils`, while the user only has `bevy::utils`. There are two affected macros. - `bevy_utils::define_label`: it may be useful in user's code for defining custom kinds of label traits (this is why I made this PR). - `bevy_asset::load_internal_asset`: not useful currently due to limitations of the debug asset server, but this may change in the future. ## Solution We can make them work by using `$crate` instead of names of their own crates, which can refer to the macro's defining crate regardless of the user's setup. Even though our objective is rather low-priority here, the solution adds no maintenance cost so it is still worthwhile.
102 lines
2.3 KiB
Rust
102 lines
2.3 KiB
Rust
//! Traits used by label implementations
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use std::{
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any::Any,
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hash::{Hash, Hasher},
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};
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pub trait DynEq: Any {
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fn as_any(&self) -> &dyn Any;
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fn dyn_eq(&self, other: &dyn DynEq) -> bool;
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}
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impl<T> DynEq for T
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where
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T: Any + Eq,
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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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fn dyn_eq(&self, other: &dyn DynEq) -> bool {
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if let Some(other) = other.as_any().downcast_ref::<T>() {
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return self == other;
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}
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false
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}
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}
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pub trait DynHash: DynEq {
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fn as_dyn_eq(&self) -> &dyn DynEq;
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fn dyn_hash(&self, state: &mut dyn Hasher);
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}
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impl<T> DynHash for T
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where
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T: DynEq + Hash,
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{
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fn as_dyn_eq(&self) -> &dyn DynEq {
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self
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}
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fn dyn_hash(&self, mut state: &mut dyn Hasher) {
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T::hash(self, &mut state);
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self.type_id().hash(&mut state);
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}
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}
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/// Macro to define a new label trait
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///
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/// # Example
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///
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/// ```
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/// # use bevy_utils::define_label;
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/// define_label!(MyNewLabelTrait);
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/// ```
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#[macro_export]
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macro_rules! define_label {
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($label_trait_name:ident) => {
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/// Defines a set of strongly-typed labels for a class of objects
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pub trait $label_trait_name:
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$crate::label::DynHash + ::std::fmt::Debug + Send + Sync + 'static
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{
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#[doc(hidden)]
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fn dyn_clone(&self) -> Box<dyn $label_trait_name>;
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}
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impl PartialEq for dyn $label_trait_name {
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fn eq(&self, other: &Self) -> bool {
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self.dyn_eq(other.as_dyn_eq())
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}
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}
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impl Eq for dyn $label_trait_name {}
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impl ::std::hash::Hash for dyn $label_trait_name {
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fn hash<H: ::std::hash::Hasher>(&self, state: &mut H) {
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self.dyn_hash(state);
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}
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}
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impl Clone for Box<dyn $label_trait_name> {
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fn clone(&self) -> Self {
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self.dyn_clone()
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}
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}
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impl $label_trait_name for ::std::borrow::Cow<'static, str> {
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fn dyn_clone(&self) -> Box<dyn $label_trait_name> {
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Box::new(self.clone())
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}
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}
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impl $label_trait_name for &'static str {
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fn dyn_clone(&self) -> Box<dyn $label_trait_name> {
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Box::new(<&str>::clone(self))
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}
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}
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};
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}
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