diff options
Diffstat (limited to 'vendor/dyn-clone/src/macros.rs')
| -rw-r--r-- | vendor/dyn-clone/src/macros.rs | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/vendor/dyn-clone/src/macros.rs b/vendor/dyn-clone/src/macros.rs new file mode 100644 index 00000000..b4c09606 --- /dev/null +++ b/vendor/dyn-clone/src/macros.rs @@ -0,0 +1,121 @@ +use crate::DynClone; + +/// Implement the standard library `Clone` for a trait object that has +/// `DynClone` as a supertrait. +/// +/// ``` +/// use dyn_clone::DynClone; +/// +/// trait MyTrait: DynClone { +/// /* ... */ +/// } +/// +/// dyn_clone::clone_trait_object!(MyTrait); +/// +/// // Now data structures containing Box<dyn MyTrait> can derive Clone. +/// #[derive(Clone)] +/// struct Container { +/// trait_object: Box<dyn MyTrait>, +/// } +/// ``` +/// +/// The macro supports traits that have type parameters and/or `where` clauses. +/// +/// ``` +/// use dyn_clone::DynClone; +/// use std::io::Read; +/// +/// trait Difficult<R>: DynClone where R: Read { +/// /* ... */ +/// } +/// +/// dyn_clone::clone_trait_object!(<R> Difficult<R> where R: Read); +/// ``` +#[macro_export] +macro_rules! clone_trait_object { + ($($path:tt)+) => { + $crate::__internal_clone_trait_object!(begin $($path)+); + }; +} + +#[doc(hidden)] +#[macro_export] +macro_rules! __internal_clone_trait_object { + // Invocation started with `<`, parse generics. + (begin < $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(generics () () $($rest)*); + }; + + // Invocation did not start with `<`. + (begin $first:tt $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(path () ($first) $($rest)*); + }; + + // End of generics. + (generics ($($generics:tt)*) () > $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(path ($($generics)*) () $($rest)*); + }; + + // Generics open bracket. + (generics ($($generics:tt)*) ($($brackets:tt)*) < $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(generics ($($generics)* <) ($($brackets)* <) $($rest)*); + }; + + // Generics close bracket. + (generics ($($generics:tt)*) (< $($brackets:tt)*) > $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(generics ($($generics)* >) ($($brackets)*) $($rest)*); + }; + + // Token inside of generics. + (generics ($($generics:tt)*) ($($brackets:tt)*) $first:tt $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(generics ($($generics)* $first) ($($brackets)*) $($rest)*); + }; + + // End with `where` clause. + (path ($($generics:tt)*) ($($path:tt)*) where $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(impl ($($generics)*) ($($path)*) ($($rest)*)); + }; + + // End without `where` clause. + (path ($($generics:tt)*) ($($path:tt)*)) => { + $crate::__internal_clone_trait_object!(impl ($($generics)*) ($($path)*) ()); + }; + + // Token inside of path. + (path ($($generics:tt)*) ($($path:tt)*) $first:tt $($rest:tt)*) => { + $crate::__internal_clone_trait_object!(path ($($generics)*) ($($path)* $first) $($rest)*); + }; + + // The impl. + (impl ($($generics:tt)*) ($($path:tt)*) ($($bound:tt)*)) => { + #[allow(unknown_lints, non_local_definitions)] // false positive: https://github.com/rust-lang/rust/issues/121621 + impl<'clone, $($generics)*> $crate::__private::Clone for $crate::__private::Box<dyn $($path)* + 'clone> where $($bound)* { + fn clone(&self) -> Self { + $crate::clone_box(&**self) + } + } + + #[allow(unknown_lints, non_local_definitions)] + impl<'clone, $($generics)*> $crate::__private::Clone for $crate::__private::Box<dyn $($path)* + $crate::__private::Send + 'clone> where $($bound)* { + fn clone(&self) -> Self { + $crate::clone_box(&**self) + } + } + + #[allow(unknown_lints, non_local_definitions)] + impl<'clone, $($generics)*> $crate::__private::Clone for $crate::__private::Box<dyn $($path)* + $crate::__private::Sync + 'clone> where $($bound)* { + fn clone(&self) -> Self { + $crate::clone_box(&**self) + } + } + + #[allow(unknown_lints, non_local_definitions)] + impl<'clone, $($generics)*> $crate::__private::Clone for $crate::__private::Box<dyn $($path)* + $crate::__private::Send + $crate::__private::Sync + 'clone> where $($bound)* { + fn clone(&self) -> Self { + $crate::clone_box(&**self) + } + } + }; +} + +clone_trait_object!(DynClone); |