2 files changed, 198 insertions, 0 deletions
diff --git a/src/castable_function/mod.rs b/src/castable_function/mod.rs
new file mode 100644
index 0000000..4c2f0db
--- /dev/null
+++ b/src/castable_function/mod.rs
@@ -0,0 +1,93 @@
+use std::any::{type_name, Any};
+use std::fmt::Debug;
+
+use crate::ptr::TransientPtr;
+
+#[cfg(feature = "async")]
+pub mod threadsafe;
+
+/// Interface for any castable function.
+pub trait AnyCastableFunction: Any + Debug
+{
+    fn as_any(&self) -> &dyn Any;
+}
+
+pub struct CastableFunction<ReturnInterface, DIContainerT>
+where
+    ReturnInterface: 'static + ?Sized,
+    DIContainerT: 'static,
+{
+    func: &'static dyn Fn(&DIContainerT) -> TransientPtr<ReturnInterface>,
+}
+
+impl<ReturnInterface, DIContainerT> CastableFunction<ReturnInterface, DIContainerT>
+where
+    ReturnInterface: 'static + ?Sized,
+{
+    pub fn new(
+        func: &'static dyn Fn(&DIContainerT) -> TransientPtr<ReturnInterface>,
+    ) -> Self
+    {
+        Self { func }
+    }
+
+    pub fn call(&self, di_container: &DIContainerT) -> TransientPtr<ReturnInterface>
+    {
+        (self.func)(di_container)
+    }
+}
+
+impl<ReturnInterface, DIContainerT> AnyCastableFunction
+    for CastableFunction<ReturnInterface, DIContainerT>
+where
+    ReturnInterface: 'static + ?Sized,
+    DIContainerT: 'static,
+{
+    fn as_any(&self) -> &dyn Any
+    {
+        self
+    }
+}
+
+impl<ReturnInterface, DIContainerT> Debug
+    for CastableFunction<ReturnInterface, DIContainerT>
+where
+    ReturnInterface: 'static + ?Sized,
+{
+    #[cfg(not(tarpaulin_include))]
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        let ret = type_name::<TransientPtr<ReturnInterface>>();
+
+        formatter.write_fmt(format_args!(
+            "CastableFunction (&DIContainer) -> {ret} {{ ... }}"
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests
+{
+    use super::*;
+    use crate::di_container::blocking::MockDIContainer;
+
+    #[derive(Debug, PartialEq, Eq)]
+    struct Bacon
+    {
+        heal_amount: u32,
+    }
+
+    #[test]
+    fn can_call()
+    {
+        let castable_func = CastableFunction::new(&|_: &MockDIContainer| {
+            TransientPtr::new(Bacon { heal_amount: 27 })
+        });
+
+        let mock_di_container = MockDIContainer::new();
+
+        let output = castable_func.call(&mock_di_container);
+
+        assert_eq!(output, TransientPtr::new(Bacon { heal_amount: 27 }));
+    }
+}
diff --git a/src/castable_function/threadsafe.rs b/src/castable_function/threadsafe.rs
new file mode 100644
index 0000000..7543396
--- /dev/null
+++ b/src/castable_function/threadsafe.rs
@@ -0,0 +1,105 @@
+use std::any::{type_name, Any};
+use std::fmt::Debug;
+
+use crate::castable_function::AnyCastableFunction;
+use crate::ptr::TransientPtr;
+
+/// Interface for any threadsafe castable function.
+pub trait AnyThreadsafeCastableFunction:
+    AnyCastableFunction + Send + Sync + Debug
+{
+}
+
+pub struct ThreadsafeCastableFunction<ReturnInterface, DIContainerT>
+where
+    DIContainerT: 'static,
+    ReturnInterface: 'static + ?Sized,
+{
+    func: &'static (dyn Fn(&DIContainerT) -> TransientPtr<ReturnInterface> + Send + Sync),
+}
+
+impl<ReturnInterface, DIContainerT>
+    ThreadsafeCastableFunction<ReturnInterface, DIContainerT>
+where
+    DIContainerT: 'static,
+    ReturnInterface: 'static + ?Sized,
+{
+    pub fn new(
+        func: &'static (dyn Fn(&DIContainerT) -> TransientPtr<ReturnInterface>
+                      + Send
+                      + Sync),
+    ) -> Self
+    {
+        Self { func }
+    }
+
+    pub fn call(&self, di_container: &DIContainerT) -> TransientPtr<ReturnInterface>
+    {
+        (self.func)(di_container)
+    }
+}
+
+impl<ReturnInterface, DIContainerT> AnyCastableFunction
+    for ThreadsafeCastableFunction<ReturnInterface, DIContainerT>
+where
+    DIContainerT: 'static,
+    ReturnInterface: 'static + ?Sized,
+{
+    fn as_any(&self) -> &dyn Any
+    {
+        self
+    }
+}
+
+impl<ReturnInterface, DIContainerT> AnyThreadsafeCastableFunction
+    for ThreadsafeCastableFunction<ReturnInterface, DIContainerT>
+where
+    DIContainerT: 'static,
+    ReturnInterface: 'static + ?Sized,
+{
+}
+
+impl<ReturnInterface, DIContainerT> Debug
+    for ThreadsafeCastableFunction<ReturnInterface, DIContainerT>
+where
+    DIContainerT: 'static,
+    ReturnInterface: 'static + ?Sized,
+{
+    #[cfg(not(tarpaulin_include))]
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        let ret = type_name::<TransientPtr<ReturnInterface>>();
+
+        formatter.write_fmt(format_args!(
+            "ThreadsafeCastableFunction(&AsyncDIContainer) -> {ret} {{ ... }}",
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests
+{
+    use super::*;
+    use crate::di_container::asynchronous::MockAsyncDIContainer;
+
+    #[derive(Debug, PartialEq, Eq)]
+    struct Bacon
+    {
+        heal_amount: u32,
+    }
+
+    #[test]
+    fn can_call()
+    {
+        let castable_function =
+            ThreadsafeCastableFunction::new(&|_: &MockAsyncDIContainer| {
+                TransientPtr::new(Bacon { heal_amount: 27 })
+            });
+
+        let mock_di_container = MockAsyncDIContainer::new();
+
+        let output = castable_function.call(&mock_di_container);
+
+        assert_eq!(output, TransientPtr::new(Bacon { heal_amount: 27 }));
+    }
+}