use fn pointer for comparisons

crates/bevy_app/src/app.rs

@@ -373,9 +373,9 @@ impl App {
  stage_label: impl StageLabel,
  system: impl IntoSystemDescriptor<Params>,
  ) -> &mut Self {
- use std::any::TypeId;
+ let stage_label = stage_label.as_label();
  assert!(
- stage_label.type_id() != TypeId::of::<StartupStage>(),
+ !stage_label.is::<StartupStage>(),
  "add systems to a startup stage using App::add_startup_system_to_stage"
  );
  self.schedule.add_system_to_stage(stage_label, system);
@@ -408,9 +408,9 @@ impl App {
  stage_label: impl StageLabel,
  system_set: SystemSet,
  ) -> &mut Self {
- use std::any::TypeId;
+ let stage_label = stage_label.as_label();
  assert!(
- stage_label.type_id() != TypeId::of::<StartupStage>(),
+ !stage_label.is::<StartupStage>(),
  "add system sets to a startup stage using App::add_startup_system_set_to_stage"
  );
  self.schedule

crates/bevy_utils/src/label.rs

@@ -72,7 +72,6 @@ macro_rules! define_label {
  $(#[$id_attr])*
  #[derive(Clone, Copy)]
  pub struct $id_name {
- ty: ::std::any::TypeId,
  data: u64,
  f: fn(u64, &mut ::std::fmt::Formatter) -> ::std::fmt::Result,
  }
@@ -89,14 +88,8 @@ macro_rules! define_label {
  /// Converts this type into an opaque, strongly-typed label.
  #[inline]
  fn as_label(&self) -> $id_name {
- let ty = self.type_id();
  let data = self.data();
- $id_name { ty, data, f: Self::fmt }
- }
- /// Returns the [`TypeId`] used to differentiate labels.
- #[inline]
- fn type_id(&self) -> ::std::any::TypeId {
- ::std::any::TypeId::of::<Self>()
+ $id_name { data, f: Self::fmt }
  }
  /// Returns a number used to distinguish different labels of the same type.
  fn data(&self) -> u64;
@@ -114,10 +107,6 @@ macro_rules! define_label {
  *self
  }
  #[inline]
- fn type_id(&self) -> ::std::any::TypeId {
- self.ty
- }
- #[inline]
  fn data(&self) -> u64 {
  self.data
  }
@@ -130,17 +119,27 @@ macro_rules! define_label {
  impl PartialEq for $id_name {
  #[inline]
  fn eq(&self, rhs: &Self) -> bool {
- self.type_id() == rhs.type_id() && self.data() == rhs.data()
+ (self.f as usize) == (rhs.f as usize) && self.data() == rhs.data()
  }
  }
  impl Eq for $id_name {}
 
 
  impl std::hash::Hash for $id_name {
  fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
- self.type_id().hash(state);
+ (self.f as usize).hash(state);
  self.data().hash(state);
  }
  }
+
+ impl $id_name {
+ /// Returns true if this label was constructed from an instance of type `L`.
+ pub fn is<L: $label_name>(self) -> bool {
+ // FIXME: This is potentially incorrect, due to the
+ // compiler unifying identical functions. We'll likely
+ // have to store some kind of hash of the TypeId.
+ (self.f as usize) == (<L as $label_name>::fmt as usize)
+ }
+ }
  };
 }