refactor(ecs): replace optional components with Option query term

6 files changed, 41 insertions, 179 deletions

diff --git a/ecs/src/component.rs b/ecs/src/component.rs
index f4c29ae..49265b3 100644
--- a/ecs/src/component.rs
+++ b/ecs/src/component.rs
@@ -51,21 +51,6 @@ pub trait Component: SystemInput + Any
 
     /// Returns the component UID of a component event for this component.
     fn get_event_uid(&self, event_kind: ComponentEventKind) -> Uid;
-
-    /// Returns whether the component `self` is optional.
-    fn self_is_optional(&self) -> bool
-    {
-        false
-    }
-
-    /// Returns whether this component is optional.
-    #[must_use]
-    fn is_optional() -> bool
-    where
-        Self: Sized,
-    {
-        false
-    }
 }
 
 impl dyn Component
@@ -94,46 +79,6 @@ impl Debug for dyn Component
     }
 }
 
-impl<ComponentT> Component for Option<ComponentT>
-where
-    ComponentT: Component,
-    for<'a> Option<ComponentT::Handle<'a>>: HandleFromEntityComponentRef<'a>,
-    for<'a> Option<ComponentT::HandleMut<'a>>: HandleFromEntityComponentRef<'a>,
-{
-    type Component = ComponentT;
-    type Handle<'component> = Option<ComponentT::Handle<'component>>;
-    type HandleMut<'component> = Option<ComponentT::HandleMut<'component>>;
-
-    fn id() -> Uid
-    {
-        ComponentT::id()
-    }
-
-    fn name(&self) -> &'static str
-    {
-        type_name::<Self>()
-    }
-
-    fn get_event_uid(&self, event_kind: ComponentEventKind) -> Uid
-    {
-        match event_kind {
-            ComponentEventKind::Removed => ComponentRemovedEvent::<Self>::id(),
-        }
-    }
-
-    fn self_is_optional(&self) -> bool
-    {
-        true
-    }
-
-    fn is_optional() -> bool
-    {
-        true
-    }
-}
-
-impl<ComponentT> SystemInput for Option<ComponentT> where ComponentT: Component {}
-
 /// A sequence of components.
 pub trait Sequence
 {
@@ -180,24 +125,14 @@ where
 pub struct Metadata
 {
     pub id: Uid,
-    pub is_optional: bool,
 }
 
 impl Metadata
 {
     #[must_use]
-    pub fn new_non_optional(id: Uid) -> Self
-    {
-        Self { id, is_optional: false }
-    }
-
-    #[must_use]
     pub fn of<ComponentT: Component>() -> Self
     {
-        Self {
-            id: ComponentT::id(),
-            is_optional: ComponentT::is_optional(),
-        }
+        Self { id: ComponentT::id() }
     }
 }
 
@@ -257,31 +192,6 @@ impl<'comp, ComponentT: Component> HandleFromEntityComponentRef<'comp>
     }
 }
 
-impl<'comp, ComponentT> HandleFromEntityComponentRef<'comp>
-    for Option<Handle<'comp, ComponentT>>
-where
-    ComponentT: Component,
-{
-    type Error = HandleError;
-
-    fn from_entity_component_ref(
-        entity_component_ref: Option<EntityComponentRef<'comp>>,
-        _world: &'comp World,
-    ) -> Result<Self, Self::Error>
-    {
-        entity_component_ref
-            .map(|entity_comp| {
-                Ok(Handle::new(
-                    entity_comp
-                        .component()
-                        .read_nonblock()
-                        .map_err(AcquireComponentLockFailed)?,
-                ))
-            })
-            .transpose()
-    }
-}
-
 impl<ComponentT: Component> Deref for Handle<'_, ComponentT>
 {
     type Target = ComponentT;
@@ -337,31 +247,6 @@ impl<'comp, ComponentT: Component> HandleFromEntityComponentRef<'comp>
     }
 }
 
-impl<'comp, ComponentT> HandleFromEntityComponentRef<'comp>
-    for Option<HandleMut<'comp, ComponentT>>
-where
-    ComponentT: Component,
-{
-    type Error = HandleError;
-
-    fn from_entity_component_ref(
-        entity_component_ref: Option<EntityComponentRef<'comp>>,
-        _world: &'comp World,
-    ) -> Result<Self, Self::Error>
-    {
-        entity_component_ref
-            .map(|entity_comp| {
-                Ok(HandleMut::new(
-                    entity_comp
-                        .component()
-                        .write_nonblock()
-                        .map_err(AcquireComponentLockFailed)?,
-                ))
-            })
-            .transpose()
-    }
-}
-
 impl<ComponentT: Component> Deref for HandleMut<'_, ComponentT>
 {
     type Target = ComponentT;
@@ -422,7 +307,6 @@ macro_rules! inner {
                         #(
                             Metadata {
                                 id: IntoComp~I::Component::id(),
-                                is_optional: IntoComp~I::Component::is_optional(),
                             },
                         )*
                     ]
diff --git a/ecs/src/component/storage/archetype.rs b/ecs/src/component/storage/archetype.rs
index 58facc9..b8ac826 100644
--- a/ecs/src/component/storage/archetype.rs
+++ b/ecs/src/component/storage/archetype.rs
@@ -282,10 +282,6 @@ impl Id
 
             prev_component_id = Some(comp_metadata.id);
 
-            if comp_metadata.is_optional {
-                continue;
-            }
-
             comp_metadata.id.hash(&mut hasher);
         }
 
diff --git a/ecs/src/lib.rs b/ecs/src/lib.rs
index ee33bd1..2c88eef 100644
--- a/ecs/src/lib.rs
+++ b/ecs/src/lib.rs
@@ -493,11 +493,6 @@ impl World
     )
     {
         for (component_id, component) in components {
-            debug_assert!(
-                !component.self_is_optional(),
-                "Adding a optional component to a entity is not supported"
-            );
-
             if let Err(err) = component_storage.add_entity_component(
                 entity_uid,
                 (component_id, component.name(), component),
diff --git a/ecs/src/query.rs b/ecs/src/query.rs
index f642156..7542f0d 100644
--- a/ecs/src/query.rs
+++ b/ecs/src/query.rs
@@ -198,10 +198,6 @@ impl_terms_builder! {
     #[allow(unused_mut)]
     fn with<ComponentT: Component>(mut self) -> Self
     {
-        if ComponentT::is_optional() {
-            return self;
-        }
-
         let insert_index = self.required_components
             .partition_point(|id| *id <= ComponentT::id());
 
@@ -214,13 +210,6 @@ impl_terms_builder! {
     #[allow(unused_mut)]
     fn without<ComponentT: Component>(mut self) -> Self
     {
-        if ComponentT::is_optional() {
-            panic!(
-                "{}::without cannot take optional component",
-                type_name::<Self>()
-            );
-        }
-
         let insert_index = self.excluded_components
             .partition_point(|id| *id <= ComponentT::id());
 
diff --git a/ecs/src/query/term.rs b/ecs/src/query/term.rs
index ce453f0..78668c5 100644
--- a/ecs/src/query/term.rs
+++ b/ecs/src/query/term.rs
@@ -1,7 +1,13 @@
+use std::any::type_name;
 use std::marker::PhantomData;
 
-use crate::component::Component;
-use crate::query::{TermWithoutField, TermsBuilder, TermsBuilderInterface};
+use crate::component::{Component, HandleFromEntityComponentRef, Ref as ComponentRef};
+use crate::query::{
+    TermWithField,
+    TermWithoutField,
+    TermsBuilder,
+    TermsBuilderInterface,
+};
 
 pub struct With<ComponentT>
 where
@@ -40,3 +46,35 @@ where
         terms_builder.without::<ComponentT>();
     }
 }
+
+impl<ComponentRefT> TermWithField for Option<ComponentRefT>
+where
+    ComponentRefT: ComponentRef,
+{
+    type Field<'a> = Option<ComponentRefT::Handle<'a>>;
+
+    fn apply_to_terms_builder<const MAX_TERM_CNT: usize>(
+        _terms_builder: &mut TermsBuilder<MAX_TERM_CNT>,
+    )
+    {
+    }
+
+    fn get_field<'world>(
+        entity_handle: &crate::entity::Handle<'world>,
+        world: &'world crate::World,
+    ) -> Self::Field<'world>
+    {
+        Some(
+            ComponentRefT::Handle::<'world>::from_entity_component_ref(
+                Some(entity_handle.get_component(ComponentRefT::Component::id())?),
+                world,
+            )
+            .unwrap_or_else(|err| {
+                panic!(
+                    "Creating handle to component {} failed: {err}",
+                    type_name::<ComponentRefT::Component>()
+                );
+            }),
+        )
+    }
+}
diff --git a/ecs/src/relationship.rs b/ecs/src/relationship.rs
index c5399e4..e368dd4 100644
--- a/ecs/src/relationship.rs
+++ b/ecs/src/relationship.rs
@@ -103,26 +103,6 @@ where
     }
 }
 
-impl<'rel_comp, Kind, ComponentT> HandleFromEntityComponentRef<'rel_comp>
-    for Option<RelationMut<'rel_comp, Kind, ComponentT>>
-where
-    ComponentT: Component,
-{
-    type Error = ComponentHandleError;
-
-    fn from_entity_component_ref(
-        entity_component_ref: Option<EntityComponentRef<'rel_comp>>,
-        world: &'rel_comp World,
-    ) -> Result<Self, Self::Error>
-    {
-        entity_component_ref
-            .map(|entity_comp| {
-                RelationMut::from_entity_component_ref(Some(entity_comp), world)
-            })
-            .transpose()
-    }
-}
-
 impl<'rel_comp, Kind, ComponentT> RelationMut<'rel_comp, Kind, ComponentT>
 where
     ComponentT: Component,
@@ -328,26 +308,6 @@ where
     }
 }
 
-impl<'rel_comp, Kind, ComponentT> HandleFromEntityComponentRef<'rel_comp>
-    for Option<Relation<'rel_comp, Kind, ComponentT>>
-where
-    ComponentT: Component,
-{
-    type Error = ComponentHandleError;
-
-    fn from_entity_component_ref(
-        entity_component_ref: Option<EntityComponentRef<'rel_comp>>,
-        world: &'rel_comp World,
-    ) -> Result<Self, ComponentHandleError>
-    {
-        entity_component_ref
-            .map(|entity_comp| {
-                Relation::from_entity_component_ref(Some(entity_comp), world)
-            })
-            .transpose()
-    }
-}
-
 impl<'rel_comp, Kind, ComponentT> Relation<'rel_comp, Kind, ComponentT>
 where
     ComponentT: Component,