fix(ecs): make optional relationships possible

2 files changed, 73 insertions, 4 deletions

diff --git a/ecs/src/component.rs b/ecs/src/component.rs
index 35e5430..b0423c5 100644
--- a/ecs/src/component.rs
+++ b/ecs/src/component.rs
@@ -9,7 +9,7 @@ use crate::event::component::{
     Removed as ComponentRemovedEvent,
 };
 use crate::lock::{Error as LockError, Lock, ReadGuard, WriteGuard};
-use crate::system::{ComponentRef, ComponentRefMut, Input as SystemInput};
+use crate::system::Input as SystemInput;
 use crate::type_name::TypeName;
 use crate::uid::Uid;
 use crate::util::Array;
@@ -105,10 +105,12 @@ impl TypeName for Box<dyn Component>
 impl<ComponentT> Component for Option<ComponentT>
 where
     ComponentT: Component,
+    for<'a> Option<ComponentT::Ref<'a>>: FromOptional<'a> + FromLockedOptional<'a>,
+    for<'a> Option<ComponentT::RefMut<'a>>: FromOptionalMut<'a> + FromLockedOptional<'a>,
 {
     type Component = ComponentT;
-    type Ref<'component> = Option<ComponentRef<'component, ComponentT>>;
-    type RefMut<'component> = Option<ComponentRefMut<'component, ComponentT>>;
+    type Ref<'component> = Option<ComponentT::Ref<'component>>;
+    type RefMut<'component> = Option<ComponentT::RefMut<'component>>;
 
     fn id() -> Uid
     {
diff --git a/ecs/src/relationship.rs b/ecs/src/relationship.rs
index d136db4..143b589 100644
--- a/ecs/src/relationship.rs
+++ b/ecs/src/relationship.rs
@@ -10,7 +10,7 @@ use crate::component::{
     FromOptional as FromOptionalComponent,
     FromOptionalMut as FromOptionalMutComponent,
 };
-use crate::lock::{Error as LockError, Lock, ReadGuard};
+use crate::lock::{Error as LockError, Lock, ReadGuard, WriteGuard};
 use crate::system::{ComponentRef, ComponentRefMut};
 use crate::uid::{Kind as UidKind, Uid};
 use crate::World;
@@ -104,6 +104,22 @@ where
     }
 }
 
+impl<'rel_comp, Kind, ComponentT> FromOptionalMutComponent<'rel_comp>
+    for Option<RelationMut<'rel_comp, Kind, ComponentT>>
+where
+    ComponentT: Component,
+{
+    fn from_optional_mut_component(
+        optional_component: Option<WriteGuard<'rel_comp, Box<dyn Component>>>,
+        world: &'rel_comp World,
+    ) -> Self
+    {
+        optional_component.map(|component| {
+            RelationMut::from_optional_mut_component(Some(component), world)
+        })
+    }
+}
+
 impl<'rel_comp, Kind, ComponentT> FromLockedOptionalComponent<'rel_comp>
     for RelationMut<'rel_comp, Kind, ComponentT>
 where
@@ -123,6 +139,24 @@ where
     }
 }
 
+impl<'rel_comp, Kind, ComponentT> FromLockedOptionalComponent<'rel_comp>
+    for Option<RelationMut<'rel_comp, Kind, ComponentT>>
+where
+    ComponentT: Component,
+{
+    fn from_locked_optional_component(
+        optional_component: Option<&'rel_comp Lock<Box<dyn Component>>>,
+        world: &'rel_comp World,
+    ) -> Result<Self, crate::lock::Error>
+    {
+        optional_component
+            .map(|component| {
+                RelationMut::from_locked_optional_component(Some(component), world)
+            })
+            .transpose()
+    }
+}
+
 impl<'rel_comp, Kind, ComponentT> RelationMut<'rel_comp, Kind, ComponentT>
 where
     ComponentT: Component,
@@ -327,6 +361,21 @@ where
     }
 }
 
+impl<'rel_comp, Kind, ComponentT> FromOptionalComponent<'rel_comp>
+    for Option<Relation<'rel_comp, Kind, ComponentT>>
+where
+    ComponentT: Component,
+{
+    fn from_optional_component(
+        optional_component: Option<ReadGuard<'rel_comp, Box<dyn Component>>>,
+        world: &'rel_comp World,
+    ) -> Self
+    {
+        optional_component
+            .map(|component| Relation::from_optional_component(Some(component), world))
+    }
+}
+
 impl<'rel_comp, Kind, ComponentT> FromLockedOptionalComponent<'rel_comp>
     for Relation<'rel_comp, Kind, ComponentT>
 where
@@ -346,6 +395,24 @@ where
     }
 }
 
+impl<'rel_comp, Kind, ComponentT> FromLockedOptionalComponent<'rel_comp>
+    for Option<Relation<'rel_comp, Kind, ComponentT>>
+where
+    ComponentT: Component,
+{
+    fn from_locked_optional_component(
+        optional_component: Option<&'rel_comp Lock<Box<dyn Component>>>,
+        world: &'rel_comp World,
+    ) -> Result<Self, crate::lock::Error>
+    {
+        optional_component
+            .map(|component| {
+                Relation::from_locked_optional_component(Some(component), world)
+            })
+            .transpose()
+    }
+}
+
 impl<'rel_comp, Kind, ComponentT> Relation<'rel_comp, Kind, ComponentT>
 where
     ComponentT: Component,