Checkpoint

2023-09-27 23:19:32 -06:00
parent 769a04517f
commit 7e49c7d782
3 changed files with 133 additions and 126 deletions
@@ -0,0 +1,90 @@
+use crate::{AppContext, Context, Effect, EntityId, Handle, Reference, WeakHandle};
+use std::{marker::PhantomData, sync::Arc};
+
+pub struct ModelContext<'a, T> {
+    app: Reference<'a, AppContext>,
+    entity_type: PhantomData<T>,
+    entity_id: EntityId,
+}
+
+impl<'a, T: Send + Sync + 'static> ModelContext<'a, T> {
+    pub(crate) fn mutable(app: &'a mut AppContext, entity_id: EntityId) -> Self {
+        Self {
+            app: Reference::Mutable(app),
+            entity_type: PhantomData,
+            entity_id,
+        }
+    }
+
+    // todo!
+    // fn update<R>(&mut self, update: impl FnOnce(&mut T, &mut Self) -> R) -> R {
+    //     let mut entity = self
+    //         .app
+    //         .entities
+    //         .get_mut(self.entity_id)
+    //         .unwrap()
+    //         .take()
+    //         .unwrap();
+    //     let result = update(entity.downcast_mut::<T>().unwrap(), self);
+    //     self.app
+    //         .entities
+    //         .get_mut(self.entity_id)
+    //         .unwrap()
+    //         .replace(entity);
+    //     result
+    // }
+
+    pub fn handle(&self) -> WeakHandle<T> {
+        WeakHandle {
+            id: self.entity_id,
+            entity_type: PhantomData,
+        }
+    }
+
+    pub fn observe<E: Send + Sync + 'static>(
+        &mut self,
+        handle: &Handle<E>,
+        on_notify: impl Fn(&mut T, Handle<E>, &mut ModelContext<'_, T>) + Send + Sync + 'static,
+    ) {
+        let this = self.handle();
+        let handle = handle.downgrade();
+        self.app
+            .observers
+            .entry(handle.id)
+            .or_default()
+            .push(Arc::new(move |cx| {
+                if let Some((this, handle)) = this.upgrade(cx).zip(handle.upgrade(cx)) {
+                    this.update(cx, |this, cx| on_notify(this, handle, cx));
+                    true
+                } else {
+                    false
+                }
+            }));
+    }
+
+    pub fn notify(&mut self) {
+        self.app
+            .pending_effects
+            .push_back(Effect::Notify(self.entity_id));
+    }
+}
+
+impl<'a, T: 'static> Context for ModelContext<'a, T> {
+    type EntityContext<'b, 'c, U: Send + Sync + 'static> = ModelContext<'b, U>;
+    type Result<U> = U;
+
+    fn entity<U: Send + Sync + 'static>(
+        &mut self,
+        build_entity: impl FnOnce(&mut Self::EntityContext<'_, '_, U>) -> U,
+    ) -> Handle<U> {
+        self.app.entity(build_entity)
+    }
+
+    fn update_entity<U: Send + Sync + 'static, R>(
+        &mut self,
+        handle: &Handle<U>,
+        update: impl FnOnce(&mut U, &mut Self::EntityContext<'_, '_, U>) -> R,
+    ) -> R {
+        self.app.update_entity(handle, update)
+    }
+}