130 lines
3.1 KiB
Rust
130 lines
3.1 KiB
Rust
//! Helper module which defines the `Any` trait to to allow dynamic value handling.
|
|
|
|
use std::{
|
|
any::{type_name, TypeId},
|
|
fmt,
|
|
};
|
|
|
|
/// An raw value of any type.
|
|
pub type Variant = dyn Any;
|
|
|
|
/// A boxed dynamic type containing any value.
|
|
pub type Dynamic = Box<Variant>;
|
|
|
|
/// A trait covering any type.
|
|
pub trait Any: std::any::Any {
|
|
/// Get the `TypeId` of this type.
|
|
fn type_id(&self) -> TypeId;
|
|
|
|
/// Get the name of this type.
|
|
fn type_name(&self) -> &'static str;
|
|
|
|
/// Convert into `Dynamic`.
|
|
fn into_dynamic(&self) -> Dynamic;
|
|
|
|
/// This type may only be implemented by `rhai`.
|
|
#[doc(hidden)]
|
|
fn _closed(&self) -> _Private;
|
|
}
|
|
|
|
impl<T: Clone + std::any::Any + ?Sized> Any for T {
|
|
fn type_id(&self) -> TypeId {
|
|
TypeId::of::<T>()
|
|
}
|
|
|
|
fn type_name(&self) -> &'static str {
|
|
type_name::<T>()
|
|
}
|
|
|
|
fn into_dynamic(&self) -> Dynamic {
|
|
Box::new(self.clone())
|
|
}
|
|
|
|
fn _closed(&self) -> _Private {
|
|
_Private
|
|
}
|
|
}
|
|
|
|
impl Variant {
|
|
/// Is this `Variant` a specific type?
|
|
pub(crate) fn is<T: Any>(&self) -> bool {
|
|
let t = TypeId::of::<T>();
|
|
let boxed = <Variant as Any>::type_id(self);
|
|
|
|
t == boxed
|
|
}
|
|
|
|
/// Get a reference of a specific type to the `Variant`.
|
|
pub(crate) fn downcast_ref<T: Any>(&self) -> Option<&T> {
|
|
if self.is::<T>() {
|
|
unsafe { Some(&*(self as *const Variant as *const T)) }
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Get a mutable reference of a specific type to the `Variant`.
|
|
pub(crate) fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
|
|
if self.is::<T>() {
|
|
unsafe { Some(&mut *(self as *mut Variant as *mut T)) }
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
impl fmt::Debug for Variant {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
f.pad("?")
|
|
}
|
|
}
|
|
|
|
impl Clone for Dynamic {
|
|
fn clone(&self) -> Self {
|
|
Any::into_dynamic(self.as_ref())
|
|
}
|
|
}
|
|
|
|
/// An extension trait that allows down-casting a `Dynamic` value to a specific type.
|
|
pub trait AnyExt: Sized {
|
|
/// Get a copy of a `Dynamic` value as a specific type.
|
|
fn downcast<T: Any + Clone>(self) -> Result<Box<T>, Self>;
|
|
|
|
/// This type may only be implemented by `rhai`.
|
|
#[doc(hidden)]
|
|
fn _closed(&self) -> _Private;
|
|
}
|
|
|
|
impl AnyExt for Dynamic {
|
|
/// Get a copy of the `Dynamic` value as a specific type.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust
|
|
/// use rhai::{Dynamic, Any, AnyExt};
|
|
///
|
|
/// let x: Dynamic = 42_u32.into_dynamic();
|
|
///
|
|
/// assert_eq!(*x.downcast::<u32>().unwrap(), 42);
|
|
/// ```
|
|
fn downcast<T: Any + Clone>(self) -> Result<Box<T>, Self> {
|
|
if self.is::<T>() {
|
|
unsafe {
|
|
let raw: *mut Variant = Box::into_raw(self);
|
|
Ok(Box::from_raw(raw as *mut T))
|
|
}
|
|
} else {
|
|
Err(self)
|
|
}
|
|
}
|
|
|
|
fn _closed(&self) -> _Private {
|
|
_Private
|
|
}
|
|
}
|
|
|
|
/// Private type which ensures that `rhai::Any` and `rhai::AnyExt` can only
|
|
/// be implemented by this crate.
|
|
#[doc(hidden)]
|
|
pub struct _Private;
|