aboutsummaryrefslogtreecommitdiff
path: root/src/private/cast/boxed.rs
diff options
context:
space:
mode:
authorHampusM <hampus@hampusmat.com>2022-11-19 15:45:12 +0100
committerHampusM <hampus@hampusmat.com>2022-11-19 15:45:12 +0100
commit9f27a925bd323e8e0864bedeb33a3c6953517ea1 (patch)
treeea5d8faaed82c58fa037fa377173bb365e1cd697 /src/private/cast/boxed.rs
parentd99cbf9fa95856cbc14a3217e1cd3f13aeb2e0b3 (diff)
refactor: reorganize non-public API items
Diffstat (limited to 'src/private/cast/boxed.rs')
-rw-r--r--src/private/cast/boxed.rs87
1 files changed, 87 insertions, 0 deletions
diff --git a/src/private/cast/boxed.rs b/src/private/cast/boxed.rs
new file mode 100644
index 0000000..074346c
--- /dev/null
+++ b/src/private/cast/boxed.rs
@@ -0,0 +1,87 @@
+//! Originally from Intertrait by CodeChain
+//!
+//! <https://github.com/CodeChain-io/intertrait>
+//! <https://crates.io/crates/intertrait/0.2.2>
+//!
+//! Licensed under either of
+//!
+//! Apache License, Version 2.0 (LICENSE-APACHE or <http://www.apache.org/licenses/LICENSE-2.0>)
+//! MIT license (LICENSE-MIT or <http://opensource.org/licenses/MIT>)
+//!
+//! at your option.
+
+use std::any::type_name;
+
+use crate::private::cast::error::CastError;
+use crate::private::cast::{get_caster, CastFrom};
+
+pub trait CastBox
+{
+ /// Casts a `Box` with `Self` into a `Box` with `Dest`.
+ fn cast<Dest: ?Sized + 'static>(self: Box<Self>) -> Result<Box<Dest>, CastError>;
+}
+
+/// A blanket implementation of `CastBox` for traits extending `CastFrom`.
+impl<CastFromSelf: ?Sized + CastFrom> CastBox for CastFromSelf
+{
+ fn cast<Dest: ?Sized + 'static>(self: Box<Self>) -> Result<Box<Dest>, CastError>
+ {
+ let caster =
+ get_caster::<Dest>((*self).type_id()).map_err(CastError::GetCasterFailed)?;
+
+ (caster.cast_box)(self.box_any()).map_err(|err| CastError::CastFailed {
+ source: err,
+ from: type_name::<Self>(),
+ to: type_name::<Dest>(),
+ })
+ }
+}
+
+#[cfg(test)]
+mod tests
+{
+ use std::any::Any;
+ use std::fmt::{Debug, Display};
+
+ use super::*;
+ use crate::test_utils::subjects;
+
+ #[test]
+ fn can_cast_box()
+ {
+ let concrete_ninja = Box::new(subjects::Ninja);
+
+ let abstract_ninja: Box<dyn subjects::INinja> = concrete_ninja;
+
+ let debug_ninja_result = abstract_ninja.cast::<dyn Debug>();
+
+ assert!(debug_ninja_result.is_ok());
+ }
+
+ #[test]
+ fn cannot_cast_box_wrong()
+ {
+ let concrete_ninja = Box::new(subjects::Ninja);
+
+ let abstract_ninja: Box<dyn subjects::INinja> = concrete_ninja;
+
+ let display_ninja_result = abstract_ninja.cast::<dyn Display>();
+
+ assert!(matches!(
+ display_ninja_result,
+ Err(CastError::GetCasterFailed(_))
+ ));
+ }
+
+ #[test]
+ fn can_cast_box_from_any()
+ {
+ let concrete_ninja = Box::new(subjects::Ninja);
+
+ let any_ninja: Box<dyn Any> = concrete_ninja;
+
+ let debug_ninja_result = any_ninja.cast::<dyn Debug>();
+
+ assert!(debug_ninja_result.is_ok());
+ }
+}