feat(engine-ecs): add support for dyn Any component handles

1 files changed, 54 insertions, 16 deletions

diff --git a/engine-ecs/src/lock.rs b/engine-ecs/src/lock.rs
index fe4e08b..3db29e8 100644
--- a/engine-ecs/src/lock.rs
+++ b/engine-ecs/src/lock.rs
@@ -82,14 +82,33 @@ pub enum Error
 }
 
 #[derive(Debug)]
-pub struct ReadGuard<'guard, Value>
+pub struct ReadGuard<'guard, Value: ?Sized>
 {
     inner: RwLockReadGuard<'guard, Value>,
     value_type_name: &'static str,
 }
 
-impl<'guard, Value> ReadGuard<'guard, Value>
+impl<'guard, Value: ?Sized> ReadGuard<'guard, Value>
 {
+    pub fn map<NewValue: ?Sized>(
+        this: Self,
+        func: impl FnOnce(&Value) -> &NewValue,
+    ) -> MappedReadGuard<'guard, NewValue>
+    {
+        let value_type_name = this.value_type_name;
+
+        // The 'inner' field cannot be moved out of ReadGuard in a normal way since
+        // ReadGuard implements Drop
+        let inner = unsafe { std::ptr::read(&raw const this.inner) };
+
+        forget(this);
+
+        MappedReadGuard {
+            inner: RwLockReadGuard::map(inner, func),
+            value_type_name: value_type_name,
+        }
+    }
+
     pub fn try_map<NewValue>(
         this: Self,
         func: impl FnOnce(&Value) -> Option<&NewValue>,
@@ -114,7 +133,7 @@ impl<'guard, Value> ReadGuard<'guard, Value>
     }
 }
 
-impl<Value> Deref for ReadGuard<'_, Value>
+impl<Value: ?Sized> Deref for ReadGuard<'_, Value>
 {
     type Target = Value;
 
@@ -124,7 +143,7 @@ impl<Value> Deref for ReadGuard<'_, Value>
     }
 }
 
-impl<Value> Drop for ReadGuard<'_, Value>
+impl<Value: ?Sized> Drop for ReadGuard<'_, Value>
 {
     fn drop(&mut self)
     {
@@ -133,13 +152,13 @@ impl<Value> Drop for ReadGuard<'_, Value>
 }
 
 #[derive(Debug)]
-pub struct MappedReadGuard<'guard, Value>
+pub struct MappedReadGuard<'guard, Value: ?Sized>
 {
     inner: MappedRwLockReadGuard<'guard, Value>,
     value_type_name: &'static str,
 }
 
-impl<Value> Deref for MappedReadGuard<'_, Value>
+impl<Value: ?Sized> Deref for MappedReadGuard<'_, Value>
 {
     type Target = Value;
 
@@ -149,7 +168,7 @@ impl<Value> Deref for MappedReadGuard<'_, Value>
     }
 }
 
-impl<Value> Drop for MappedReadGuard<'_, Value>
+impl<Value: ?Sized> Drop for MappedReadGuard<'_, Value>
 {
     fn drop(&mut self)
     {
@@ -161,14 +180,33 @@ impl<Value> Drop for MappedReadGuard<'_, Value>
 }
 
 #[derive(Debug)]
-pub struct WriteGuard<'guard, Value>
+pub struct WriteGuard<'guard, Value: ?Sized>
 {
     inner: RwLockWriteGuard<'guard, Value>,
     value_type_name: &'static str,
 }
 
-impl<'guard, Value> WriteGuard<'guard, Value>
+impl<'guard, Value: ?Sized> WriteGuard<'guard, Value>
 {
+    pub fn map<NewValue: ?Sized>(
+        this: Self,
+        func: impl FnOnce(&mut Value) -> &mut NewValue,
+    ) -> MappedWriteGuard<'guard, NewValue>
+    {
+        let value_type_name = this.value_type_name;
+
+        // The 'inner' field cannot be moved out of ReadGuard in a normal way since
+        // ReadGuard implements Drop
+        let inner = unsafe { std::ptr::read(&raw const this.inner) };
+
+        forget(this);
+
+        MappedWriteGuard {
+            inner: RwLockWriteGuard::map(inner, func),
+            value_type_name: value_type_name,
+        }
+    }
+
     pub fn try_map<NewValue>(
         this: Self,
         func: impl FnOnce(&mut Value) -> Option<&mut NewValue>,
@@ -193,7 +231,7 @@ impl<'guard, Value> WriteGuard<'guard, Value>
     }
 }
 
-impl<Value> Deref for WriteGuard<'_, Value>
+impl<Value: ?Sized> Deref for WriteGuard<'_, Value>
 {
     type Target = Value;
 
@@ -203,7 +241,7 @@ impl<Value> Deref for WriteGuard<'_, Value>
     }
 }
 
-impl<Value> DerefMut for WriteGuard<'_, Value>
+impl<Value: ?Sized> DerefMut for WriteGuard<'_, Value>
 {
     fn deref_mut(&mut self) -> &mut Self::Target
     {
@@ -211,7 +249,7 @@ impl<Value> DerefMut for WriteGuard<'_, Value>
     }
 }
 
-impl<Value> Drop for WriteGuard<'_, Value>
+impl<Value: ?Sized> Drop for WriteGuard<'_, Value>
 {
     fn drop(&mut self)
     {
@@ -223,13 +261,13 @@ impl<Value> Drop for WriteGuard<'_, Value>
 }
 
 #[derive(Debug)]
-pub struct MappedWriteGuard<'guard, Value>
+pub struct MappedWriteGuard<'guard, Value: ?Sized>
 {
     inner: MappedRwLockWriteGuard<'guard, Value>,
     value_type_name: &'static str,
 }
 
-impl<Value> Deref for MappedWriteGuard<'_, Value>
+impl<Value: ?Sized> Deref for MappedWriteGuard<'_, Value>
 {
     type Target = Value;
 
@@ -239,7 +277,7 @@ impl<Value> Deref for MappedWriteGuard<'_, Value>
     }
 }
 
-impl<Value> DerefMut for MappedWriteGuard<'_, Value>
+impl<Value: ?Sized> DerefMut for MappedWriteGuard<'_, Value>
 {
     fn deref_mut(&mut self) -> &mut Self::Target
     {
@@ -247,7 +285,7 @@ impl<Value> DerefMut for MappedWriteGuard<'_, Value>
     }
 }
 
-impl<Value> Drop for MappedWriteGuard<'_, Value>
+impl<Value: ?Sized> Drop for MappedWriteGuard<'_, Value>
 {
     fn drop(&mut self)
     {