From 0fbe50549e5bc69f53ed488c4d70c2c9f929e615 Mon Sep 17 00:00:00 2001
From: Filipe Rodrigues <filipejacintorodrigues1@gmail.com>
Date: Tue, 20 May 2025 18:50:17 +0100
Subject: [PATCH] Added `dynatos_loadable::{LoadableBorrow, LoadableBorrowMut,
 SignalBorrowLoadable, SignalBorrowMutLoadable}`.

---
 dynatos-loadable/src/lib.rs             |   2 +
 dynatos-loadable/src/loadable_borrow.rs | 149 ++++++++++++++++++++++++
 2 files changed, 151 insertions(+)
 create mode 100644 dynatos-loadable/src/loadable_borrow.rs

diff --git a/dynatos-loadable/src/lib.rs b/dynatos-loadable/src/lib.rs
index bef8ab0..6090e51 100644
--- a/dynatos-loadable/src/lib.rs
+++ b/dynatos-loadable/src/lib.rs
@@ -5,10 +5,12 @@
 
 // Modules
 pub mod loadable;
+pub mod loadable_borrow;
 pub mod loadable_signal;
 
 // Exports
 pub use self::{
 	loadable::{IntoLoaded, IteratorLoadableExt, Loadable},
+	loadable_borrow::{LoadableBorrow, LoadableBorrowMut, SignalBorrowLoadable, SignalBorrowMutLoadable},
 	loadable_signal::LoadableSignal,
 };
diff --git a/dynatos-loadable/src/loadable_borrow.rs b/dynatos-loadable/src/loadable_borrow.rs
new file mode 100644
index 0000000..44c1c8f
--- /dev/null
+++ b/dynatos-loadable/src/loadable_borrow.rs
@@ -0,0 +1,149 @@
+//! Loadable borrow
+
+// Imports
+use {
+	crate::Loadable,
+	core::{
+		fmt,
+		ops::{Deref, DerefMut},
+	},
+	dynatos_reactive::{SignalBorrow, SignalBorrowMut},
+};
+
+/// Loadable borrow.
+///
+/// Allows transforming a signal borrow `Borrow<Loadable<T, E>>` into a
+/// `Loadable<Borrow<T>, E>`.
+#[derive(Clone, Copy)]
+pub struct LoadableBorrow<B>(B);
+
+impl<B, T, E> fmt::Debug for LoadableBorrow<B>
+where
+	B: Deref<Target = Loadable<T, E>>,
+	T: fmt::Debug,
+	E: 'static,
+{
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		(**self).fmt(f)
+	}
+}
+
+impl<B, T, E> Deref for LoadableBorrow<B>
+where
+	B: Deref<Target = Loadable<T, E>>,
+	E: 'static,
+{
+	type Target = T;
+
+	#[track_caller]
+	fn deref(&self) -> &Self::Target {
+		match &*self.0 {
+			Loadable::Loaded(value) => value,
+			_ => panic!("Loadable should be loaded"),
+		}
+	}
+}
+
+/// Extension trait to borrow with a [`LoadableBorrow`]
+#[extend::ext(name = SignalBorrowLoadable)]
+pub impl<S, T, E> S
+where
+	S: for<'a> SignalBorrow<Ref<'a>: Deref<Target = Loadable<T, E>>>,
+	E: Clone,
+{
+	/// Borrows this signal as a `Loadable<Borrow<T>, E>`
+	fn borrow_loadable(&self) -> Loadable<LoadableBorrow<S::Ref<'_>>, E> {
+		let borrow = self.borrow();
+		match &*borrow {
+			Loadable::Empty => Loadable::Empty,
+			Loadable::Err(err) => Loadable::Err(err.clone()),
+			Loadable::Loaded(_) => Loadable::Loaded(LoadableBorrow(borrow)),
+		}
+	}
+
+	/// Borrows this signal as a `Loadable<Borrow<T>, E>`, without adding a dependency
+	fn borrow_loadable_raw(&self) -> Loadable<LoadableBorrow<S::Ref<'_>>, E> {
+		let borrow = self.borrow_raw();
+		match &*borrow {
+			Loadable::Empty => Loadable::Empty,
+			Loadable::Err(err) => Loadable::Err(err.clone()),
+			Loadable::Loaded(_) => Loadable::Loaded(LoadableBorrow(borrow)),
+		}
+	}
+}
+
+/// Loadable mutable borrow.
+///
+/// Allows transforming a signal mutable borrow `Borrow<Loadable<T, E>>` into a
+/// `Loadable<Borrow<T>, E>`.
+#[derive(Clone, Copy)]
+pub struct LoadableBorrowMut<B>(B);
+
+impl<B, T, E> fmt::Debug for LoadableBorrowMut<B>
+where
+	B: Deref<Target = Loadable<T, E>>,
+	T: fmt::Debug,
+	E: 'static,
+{
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		(**self).fmt(f)
+	}
+}
+
+impl<B, T, E> Deref for LoadableBorrowMut<B>
+where
+	B: Deref<Target = Loadable<T, E>>,
+	E: 'static,
+{
+	type Target = T;
+
+	#[track_caller]
+	fn deref(&self) -> &Self::Target {
+		match &*self.0 {
+			Loadable::Loaded(value) => value,
+			_ => panic!("Loadable should be loaded"),
+		}
+	}
+}
+
+impl<B, T, E> DerefMut for LoadableBorrowMut<B>
+where
+	B: DerefMut<Target = Loadable<T, E>>,
+	E: 'static,
+{
+	#[track_caller]
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		match &mut *self.0 {
+			Loadable::Loaded(value) => value,
+			_ => panic!("Loadable should be loaded"),
+		}
+	}
+}
+
+/// Extension trait to borrow with a [`LoadableBorrowMut`]
+#[extend::ext(name = SignalBorrowMutLoadable)]
+pub impl<S, T, E> S
+where
+	S: for<'a> SignalBorrowMut<RefMut<'a>: DerefMut<Target = Loadable<T, E>>>,
+	E: Clone,
+{
+	/// Borrows this signal as a `Loadable<Borrow<T>, E>`
+	fn borrow_mut_loadable(&self) -> Loadable<LoadableBorrow<S::RefMut<'_>>, E> {
+		let borrow = self.borrow_mut();
+		match &*borrow {
+			Loadable::Empty => Loadable::Empty,
+			Loadable::Err(err) => Loadable::Err(err.clone()),
+			Loadable::Loaded(_) => Loadable::Loaded(LoadableBorrow(borrow)),
+		}
+	}
+
+	/// Borrows this signal as a `Loadable<Borrow<T>, E>`, without adding a dependency
+	fn borrow_mut_loadable_raw(&self) -> Loadable<LoadableBorrow<S::RefMut<'_>>, E> {
+		let borrow = self.borrow_mut_raw();
+		match &*borrow {
+			Loadable::Empty => Loadable::Empty,
+			Loadable::Err(err) => Loadable::Err(err.clone()),
+			Loadable::Loaded(_) => Loadable::Loaded(LoadableBorrow(borrow)),
+		}
+	}
+}