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authorHampusM <hampus@hampusmat.com>2022-08-30 18:53:23 +0200
committerHampusM <hampus@hampusmat.com>2022-08-30 18:53:23 +0200
commitd6f01bd571753dc2e9628418f94f66139438bcb3 (patch)
tree1ed5492d8abdeb9231d498e9ecf349c7cc1ec3d8 /src/libs/intertrait
parent080cc42bb1da09059dbc35049a7ded0649961e0c (diff)
refactor: replace arc cast panic with an error
Diffstat (limited to 'src/libs/intertrait')
-rw-r--r--src/libs/intertrait/cast/arc.rs21
-rw-r--r--src/libs/intertrait/cast/box.rs4
-rw-r--r--src/libs/intertrait/cast/error.rs3
-rw-r--r--src/libs/intertrait/cast/rc.rs4
-rw-r--r--src/libs/intertrait/mod.rs25
5 files changed, 29 insertions, 28 deletions
diff --git a/src/libs/intertrait/cast/arc.rs b/src/libs/intertrait/cast/arc.rs
index 94c0482..33d84d2 100644
--- a/src/libs/intertrait/cast/arc.rs
+++ b/src/libs/intertrait/cast/arc.rs
@@ -13,7 +13,7 @@ use std::any::type_name;
use std::sync::Arc;
use crate::libs::intertrait::cast::error::CastError;
-use crate::libs::intertrait::{caster, CastFromSync};
+use crate::libs::intertrait::{get_caster, CastFromSync};
pub trait CastArc
{
@@ -31,12 +31,19 @@ impl<CastFromSelf: ?Sized + CastFromSync> CastArc for CastFromSelf
self: Arc<Self>,
) -> Result<Arc<OtherTrait>, CastError>
{
- match caster::<OtherTrait>((*self).type_id()) {
- Some(caster) => Ok((caster.cast_arc)(self.arc_any())),
- None => Err(CastError::CastFailed {
- from: type_name::<CastFromSelf>(),
- to: type_name::<OtherTrait>(),
- }),
+ let caster = get_caster::<OtherTrait>((*self).type_id()).map_or_else(
+ || {
+ Err(CastError::CastFailed {
+ from: type_name::<CastFromSelf>(),
+ to: type_name::<OtherTrait>(),
+ })
+ },
+ Ok,
+ )?;
+
+ match caster.opt_cast_arc {
+ Some(cast_arc) => Ok(cast_arc(self.arc_any())),
+ None => Err(CastError::NotArcCastable(type_name::<OtherTrait>())),
}
}
}
diff --git a/src/libs/intertrait/cast/box.rs b/src/libs/intertrait/cast/box.rs
index 31f06db..c463c2f 100644
--- a/src/libs/intertrait/cast/box.rs
+++ b/src/libs/intertrait/cast/box.rs
@@ -13,7 +13,7 @@
use std::any::type_name;
use crate::libs::intertrait::cast::error::CastError;
-use crate::libs::intertrait::{caster, CastFrom};
+use crate::libs::intertrait::{get_caster, CastFrom};
pub trait CastBox
{
@@ -30,7 +30,7 @@ impl<CastFromSelf: ?Sized + CastFrom> CastBox for CastFromSelf
self: Box<Self>,
) -> Result<Box<OtherTrait>, CastError>
{
- match caster::<OtherTrait>((*self).type_id()) {
+ match get_caster::<OtherTrait>((*self).type_id()) {
Some(caster) => Ok((caster.cast_box)(self.box_any())),
None => Err(CastError::CastFailed {
from: type_name::<CastFromSelf>(),
diff --git a/src/libs/intertrait/cast/error.rs b/src/libs/intertrait/cast/error.rs
index 74eb3ca..a834c05 100644
--- a/src/libs/intertrait/cast/error.rs
+++ b/src/libs/intertrait/cast/error.rs
@@ -7,4 +7,7 @@ pub enum CastError
from: &'static str,
to: &'static str,
},
+
+ #[error("Trait '{0}' can't be cast to Arc")]
+ NotArcCastable(&'static str),
}
diff --git a/src/libs/intertrait/cast/rc.rs b/src/libs/intertrait/cast/rc.rs
index dfb71c2..63c0024 100644
--- a/src/libs/intertrait/cast/rc.rs
+++ b/src/libs/intertrait/cast/rc.rs
@@ -13,7 +13,7 @@ use std::any::type_name;
use std::rc::Rc;
use crate::libs::intertrait::cast::error::CastError;
-use crate::libs::intertrait::{caster, CastFrom};
+use crate::libs::intertrait::{get_caster, CastFrom};
pub trait CastRc
{
@@ -30,7 +30,7 @@ impl<CastFromSelf: ?Sized + CastFrom> CastRc for CastFromSelf
self: Rc<Self>,
) -> Result<Rc<OtherTrait>, CastError>
{
- match caster::<OtherTrait>((*self).type_id()) {
+ match get_caster::<OtherTrait>((*self).type_id()) {
Some(caster) => Ok((caster.cast_rc)(self.rc_any())),
None => Err(CastError::CastFailed {
from: type_name::<CastFromSelf>(),
diff --git a/src/libs/intertrait/mod.rs b/src/libs/intertrait/mod.rs
index bdae4c7..3b3e9ba 100644
--- a/src/libs/intertrait/mod.rs
+++ b/src/libs/intertrait/mod.rs
@@ -23,7 +23,7 @@
//! MIT license (LICENSE-MIT or <http://opensource.org/licenses/MIT>)
//!
//! at your option.
-use std::any::{type_name, Any, TypeId};
+use std::any::{Any, TypeId};
use std::rc::Rc;
use std::sync::Arc;
@@ -58,22 +58,12 @@ static CASTER_MAP: Lazy<AHashMap<(TypeId, TypeId), BoxedCaster>> = Lazy::new(||
.collect()
});
-fn cast_arc_panic<Trait: ?Sized + 'static>(_: Arc<dyn Any + Sync + Send>) -> Arc<Trait>
-{
- panic!(
- "Interface trait '{}' has not been marked async",
- type_name::<Trait>()
- )
-}
+type CastArcFn<Trait> = fn(from: Arc<dyn Any + Sync + Send + 'static>) -> Arc<Trait>;
/// A `Caster` knows how to cast a reference to or `Box` of a trait object for `Any`
/// to a trait object of trait `Trait`. Each `Caster` instance is specific to a concrete
/// type. That is, it knows how to cast to single specific trait implemented by single
/// specific type.
-///
-/// An implementation of a trait for a concrete type doesn't need to manually provide
-/// a `Caster`. Instead attach `#[cast_to]` to the `impl` block.
-#[doc(hidden)]
pub struct Caster<Trait: ?Sized + 'static>
{
/// Casts a `Box` holding a trait object for `Any` to another `Box` holding a trait
@@ -86,7 +76,7 @@ pub struct Caster<Trait: ?Sized + 'static>
/// Casts an `Arc` holding a trait object for `Any + Sync + Send + 'static`
/// to another `Arc` holding a trait object for trait `Trait`.
- pub cast_arc: fn(from: Arc<dyn Any + Sync + Send + 'static>) -> Arc<Trait>,
+ pub opt_cast_arc: Option<CastArcFn<Trait>>,
}
impl<Trait: ?Sized + 'static> Caster<Trait>
@@ -99,7 +89,7 @@ impl<Trait: ?Sized + 'static> Caster<Trait>
Caster::<Trait> {
cast_box,
cast_rc,
- cast_arc: cast_arc_panic,
+ opt_cast_arc: None,
}
}
@@ -113,14 +103,15 @@ impl<Trait: ?Sized + 'static> Caster<Trait>
Caster::<Trait> {
cast_box,
cast_rc,
- cast_arc,
+ opt_cast_arc: Some(cast_arc),
}
}
}
/// Returns a `Caster<S, Trait>` from a concrete type `S` to a trait `Trait` implemented
/// by it.
-fn caster<Trait: ?Sized + 'static>(type_id: TypeId) -> Option<&'static Caster<Trait>>
+fn get_caster<Trait: ?Sized + 'static>(type_id: TypeId)
+ -> Option<&'static Caster<Trait>>
{
CASTER_MAP
.get(&(type_id, TypeId::of::<Caster<Trait>>()))
@@ -250,7 +241,7 @@ mod tests
let caster = Box::new(Caster::<dyn Debug> {
cast_box: |from| from.downcast::<TestStruct>().unwrap(),
cast_rc: |from| from.downcast::<TestStruct>().unwrap(),
- cast_arc: |from| from.downcast::<TestStruct>().unwrap(),
+ opt_cast_arc: Some(|from| from.downcast::<TestStruct>().unwrap()),
});
(type_id, caster)
}