rhai/src/any.rs

658 lines
22 KiB
Rust

//! Helper module which defines the `Any` trait to to allow dynamic value handling.
use crate::fn_native::{FnPtr, SendSync};
use crate::parser::{ImmutableString, INT};
use crate::r#unsafe::{unsafe_cast_box, unsafe_try_cast};
#[cfg(not(feature = "no_float"))]
use crate::parser::FLOAT;
#[cfg(not(feature = "no_index"))]
use crate::engine::Array;
#[cfg(not(feature = "no_object"))]
use crate::engine::Map;
use crate::stdlib::{
any::{type_name, Any, TypeId},
boxed::Box,
collections::HashMap,
fmt,
string::String,
vec::Vec,
};
#[cfg(not(feature = "no_std"))]
#[cfg(not(target_arch = "wasm32"))]
use crate::stdlib::time::Instant;
#[cfg(not(feature = "no_std"))]
#[cfg(target_arch = "wasm32")]
use instant::Instant;
/// Trait to represent any type.
///
/// Currently, `Variant` is not `Send` nor `Sync`, so it can practically be any type.
/// Turn on the `sync` feature to restrict it to only types that implement `Send + Sync`.
#[cfg(not(feature = "sync"))]
pub trait Variant: Any {
/// Convert this `Variant` trait object to `&dyn Any`.
fn as_any(&self) -> &dyn Any;
/// Convert this `Variant` trait object to `&mut dyn Any`.
fn as_mut_any(&mut self) -> &mut dyn Any;
/// Convert this `Variant` trait object to an `Any` trait object.
fn as_box_any(self: Box<Self>) -> Box<dyn Any>;
/// Get the name of this type.
fn type_name(&self) -> &'static str;
/// Convert into `Dynamic`.
fn into_dynamic(self) -> Dynamic;
/// Clone into `Dynamic`.
fn clone_into_dynamic(&self) -> Dynamic;
/// This trait may only be implemented by `rhai`.
#[doc(hidden)]
fn _closed(&self) -> _Private;
}
/// Trait to represent any type.
///
/// `From<_>` is implemented for `i64` (`i32` if `only_i32`), `f64` (if not `no_float`),
/// `bool`, `String`, `char`, `Vec<T>` (into `Array`) and `HashMap<String, T>` (into `Map`).
#[cfg(feature = "sync")]
pub trait Variant: Any + Send + Sync {
/// Convert this `Variant` trait object to `&dyn Any`.
fn as_any(&self) -> &dyn Any;
/// Convert this `Variant` trait object to `&mut dyn Any`.
fn as_mut_any(&mut self) -> &mut dyn Any;
/// Convert this `Variant` trait object to an `Any` trait object.
fn as_box_any(self: Box<Self>) -> Box<dyn Any>;
/// Get the name of this type.
fn type_name(&self) -> &'static str;
/// Convert into `Dynamic`.
fn into_dynamic(self) -> Dynamic;
/// Clone into `Dynamic`.
fn clone_into_dynamic(&self) -> Dynamic;
/// This trait may only be implemented by `rhai`.
#[doc(hidden)]
fn _closed(&self) -> _Private;
}
impl<T: Any + Clone + SendSync> Variant for T {
fn as_any(&self) -> &dyn Any {
self
}
fn as_mut_any(&mut self) -> &mut dyn Any {
self
}
fn as_box_any(self: Box<Self>) -> Box<dyn Any> {
self
}
fn type_name(&self) -> &'static str {
type_name::<T>()
}
fn into_dynamic(self) -> Dynamic {
Dynamic::from(self)
}
fn clone_into_dynamic(&self) -> Dynamic {
Dynamic::from(self.clone())
}
fn _closed(&self) -> _Private {
_Private
}
}
impl dyn Variant {
/// Is this `Variant` a specific type?
pub fn is<T: Any>(&self) -> bool {
TypeId::of::<T>() == self.type_id()
}
}
/// Dynamic type containing any value.
pub struct Dynamic(pub(crate) Union);
/// Internal `Dynamic` representation.
///
/// Most variants are boxed to reduce the size.
pub enum Union {
Unit(()),
Bool(bool),
Str(ImmutableString),
Char(char),
Int(INT),
#[cfg(not(feature = "no_float"))]
Float(FLOAT),
#[cfg(not(feature = "no_index"))]
Array(Box<Array>),
#[cfg(not(feature = "no_object"))]
Map(Box<Map>),
FnPtr(FnPtr),
Variant(Box<Box<dyn Variant>>),
}
impl Dynamic {
/// Does this `Dynamic` hold a variant data type
/// instead of one of the support system primitive types?
pub fn is_variant(&self) -> bool {
match self.0 {
Union::Variant(_) => true,
_ => false,
}
}
/// Is the value held by this `Dynamic` a particular type?
pub fn is<T: Variant + Clone>(&self) -> bool {
self.type_id() == TypeId::of::<T>()
|| match self.0 {
Union::Str(_) => TypeId::of::<String>() == TypeId::of::<T>(),
_ => false,
}
}
/// Get the TypeId of the value held by this `Dynamic`.
pub fn type_id(&self) -> TypeId {
match &self.0 {
Union::Unit(_) => TypeId::of::<()>(),
Union::Bool(_) => TypeId::of::<bool>(),
Union::Str(_) => TypeId::of::<ImmutableString>(),
Union::Char(_) => TypeId::of::<char>(),
Union::Int(_) => TypeId::of::<INT>(),
#[cfg(not(feature = "no_float"))]
Union::Float(_) => TypeId::of::<FLOAT>(),
#[cfg(not(feature = "no_index"))]
Union::Array(_) => TypeId::of::<Array>(),
#[cfg(not(feature = "no_object"))]
Union::Map(_) => TypeId::of::<Map>(),
Union::FnPtr(_) => TypeId::of::<FnPtr>(),
Union::Variant(value) => (***value).type_id(),
}
}
/// Get the name of the type of the value held by this `Dynamic`.
pub fn type_name(&self) -> &'static str {
match &self.0 {
Union::Unit(_) => "()",
Union::Bool(_) => "bool",
Union::Str(_) => "string",
Union::Char(_) => "char",
Union::Int(_) => type_name::<INT>(),
#[cfg(not(feature = "no_float"))]
Union::Float(_) => type_name::<FLOAT>(),
#[cfg(not(feature = "no_index"))]
Union::Array(_) => "array",
#[cfg(not(feature = "no_object"))]
Union::Map(_) => "map",
Union::FnPtr(_) => "Fn",
#[cfg(not(feature = "no_std"))]
Union::Variant(value) if value.is::<Instant>() => "timestamp",
Union::Variant(value) => (***value).type_name(),
}
}
}
/// Map the name of a standard type into a friendly form.
pub(crate) fn map_std_type_name(name: &str) -> &str {
if name == type_name::<String>() {
"string"
} else if name == type_name::<ImmutableString>() {
"string"
} else if name == type_name::<&str>() {
"string"
} else if name == type_name::<FnPtr>() {
"Fn"
} else {
#[cfg(not(feature = "no_std"))]
if name == type_name::<Instant>() {
return "timestamp";
}
#[cfg(not(feature = "no_index"))]
if name == type_name::<Array>() {
return "array";
}
#[cfg(not(feature = "no_object"))]
if name == type_name::<Map>() {
return "map";
}
name
}
}
impl fmt::Display for Dynamic {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.0 {
Union::Unit(_) => write!(f, ""),
Union::Bool(value) => fmt::Display::fmt(value, f),
Union::Str(value) => fmt::Display::fmt(value, f),
Union::Char(value) => fmt::Display::fmt(value, f),
Union::Int(value) => fmt::Display::fmt(value, f),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => fmt::Display::fmt(value, f),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => fmt::Debug::fmt(value, f),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => {
f.write_str("#")?;
fmt::Debug::fmt(value, f)
}
Union::FnPtr(value) => fmt::Display::fmt(value, f),
#[cfg(not(feature = "no_std"))]
Union::Variant(value) if value.is::<Instant>() => write!(f, "<timestamp>"),
Union::Variant(value) => write!(f, "{}", (*value).type_name()),
}
}
}
impl fmt::Debug for Dynamic {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.0 {
Union::Unit(value) => fmt::Debug::fmt(value, f),
Union::Bool(value) => fmt::Debug::fmt(value, f),
Union::Str(value) => fmt::Debug::fmt(value, f),
Union::Char(value) => fmt::Debug::fmt(value, f),
Union::Int(value) => fmt::Debug::fmt(value, f),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => fmt::Debug::fmt(value, f),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => fmt::Debug::fmt(value, f),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => {
f.write_str("#")?;
fmt::Debug::fmt(value, f)
}
Union::FnPtr(value) => fmt::Display::fmt(value, f),
#[cfg(not(feature = "no_std"))]
Union::Variant(value) if value.is::<Instant>() => write!(f, "<timestamp>"),
Union::Variant(value) => write!(f, "{}", (*value).type_name()),
}
}
}
impl Clone for Dynamic {
fn clone(&self) -> Self {
match self.0 {
Union::Unit(value) => Self(Union::Unit(value)),
Union::Bool(value) => Self(Union::Bool(value)),
Union::Str(ref value) => Self(Union::Str(value.clone())),
Union::Char(value) => Self(Union::Char(value)),
Union::Int(value) => Self(Union::Int(value)),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => Self(Union::Float(value)),
#[cfg(not(feature = "no_index"))]
Union::Array(ref value) => Self(Union::Array(value.clone())),
#[cfg(not(feature = "no_object"))]
Union::Map(ref value) => Self(Union::Map(value.clone())),
Union::FnPtr(ref value) => Self(Union::FnPtr(value.clone())),
Union::Variant(ref value) => (***value).clone_into_dynamic(),
}
}
}
impl Default for Dynamic {
fn default() -> Self {
Self(Union::Unit(()))
}
}
impl Dynamic {
/// Create a `Dynamic` from any type. A `Dynamic` value is simply returned as is.
///
/// # Safety
///
/// This type uses some unsafe code, mainly for type casting.
///
/// # Notes
///
/// Beware that you need to pass in an `Array` type for it to be recognized as an `Array`.
/// A `Vec<T>` does not get automatically converted to an `Array`, but will be a generic
/// restricted trait object instead, because `Vec<T>` is not a supported standard type.
///
/// Similarly, passing in a `HashMap<String, T>` will not get a `Map` but a trait object.
///
/// # Examples
///
/// ```
/// use rhai::Dynamic;
///
/// let result = Dynamic::from(42_i64);
/// assert_eq!(result.type_name(), "i64");
/// assert_eq!(result.to_string(), "42");
///
/// let result = Dynamic::from("hello".to_string());
/// assert_eq!(result.type_name(), "string");
/// assert_eq!(result.to_string(), "hello");
///
/// let new_result = Dynamic::from(result);
/// assert_eq!(new_result.type_name(), "string");
/// assert_eq!(new_result.to_string(), "hello");
/// ```
pub fn from<T: Variant + Clone>(value: T) -> Self {
if let Some(result) = <dyn Any>::downcast_ref::<()>(&value) {
return result.clone().into();
} else if let Some(result) = <dyn Any>::downcast_ref::<bool>(&value) {
return result.clone().into();
} else if let Some(result) = <dyn Any>::downcast_ref::<INT>(&value) {
return result.clone().into();
} else if let Some(result) = <dyn Any>::downcast_ref::<char>(&value) {
return result.clone().into();
} else if let Some(result) = <dyn Any>::downcast_ref::<ImmutableString>(&value) {
return result.clone().into();
}
#[cfg(not(feature = "no_float"))]
if let Some(result) = <dyn Any>::downcast_ref::<FLOAT>(&value) {
return result.clone().into();
}
let mut boxed = Box::new(value);
boxed = match unsafe_cast_box::<_, Dynamic>(boxed) {
Ok(d) => return *d,
Err(val) => val,
};
boxed = match unsafe_cast_box::<_, String>(boxed) {
Ok(s) => return (*s).into(),
Err(val) => val,
};
#[cfg(not(feature = "no_index"))]
{
boxed = match unsafe_cast_box::<_, Array>(boxed) {
Ok(array) => return (*array).into(),
Err(val) => val,
};
}
#[cfg(not(feature = "no_object"))]
{
boxed = match unsafe_cast_box::<_, Map>(boxed) {
Ok(map) => return (*map).into(),
Err(val) => val,
}
}
Self(Union::Variant(Box::new(boxed)))
}
/// Get a copy of the `Dynamic` value as a specific type.
/// Casting to a `Dynamic` just returns as is.
///
/// Returns an error with the name of the value's actual type when the cast fails.
///
/// # Example
///
/// ```
/// use rhai::Dynamic;
///
/// let x = Dynamic::from(42_u32);
///
/// assert_eq!(x.try_cast::<u32>().unwrap(), 42);
/// ```
pub fn try_cast<T: Variant>(self) -> Option<T> {
let type_id = TypeId::of::<T>();
if type_id == TypeId::of::<Dynamic>() {
return unsafe_cast_box::<_, T>(Box::new(self)).ok().map(|v| *v);
}
match self.0 {
Union::Unit(value) => unsafe_try_cast(value),
Union::Bool(value) => unsafe_try_cast(value),
Union::Str(value) if type_id == TypeId::of::<ImmutableString>() => {
unsafe_try_cast(value)
}
Union::Str(value) => unsafe_try_cast(value.into_owned()),
Union::Char(value) => unsafe_try_cast(value),
Union::Int(value) => unsafe_try_cast(value),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => unsafe_try_cast(value),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => unsafe_cast_box::<_, T>(value).ok().map(|v| *v),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => unsafe_cast_box::<_, T>(value).ok().map(|v| *v),
Union::FnPtr(value) => unsafe_try_cast(value),
Union::Variant(value) => (*value).as_box_any().downcast().map(|x| *x).ok(),
}
}
/// Get a copy of the `Dynamic` value as a specific type.
/// Casting to a `Dynamic` just returns as is.
///
/// # Panics
///
/// Panics if the cast fails (e.g. the type of the actual value is not the same as the specified type).
///
/// # Example
///
/// ```
/// use rhai::Dynamic;
///
/// let x = Dynamic::from(42_u32);
///
/// assert_eq!(x.cast::<u32>(), 42);
/// ```
pub fn cast<T: Variant + Clone>(self) -> T {
let type_id = TypeId::of::<T>();
if type_id == TypeId::of::<Dynamic>() {
return *unsafe_cast_box::<_, T>(Box::new(self)).unwrap();
}
match self.0 {
Union::Unit(value) => unsafe_try_cast(value).unwrap(),
Union::Bool(value) => unsafe_try_cast(value).unwrap(),
Union::Str(value) if type_id == TypeId::of::<ImmutableString>() => {
unsafe_try_cast(value).unwrap()
}
Union::Str(value) => unsafe_try_cast(value.into_owned()).unwrap(),
Union::Char(value) => unsafe_try_cast(value).unwrap(),
Union::Int(value) => unsafe_try_cast(value).unwrap(),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => unsafe_try_cast(value).unwrap(),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => *unsafe_cast_box::<_, T>(value).unwrap(),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => *unsafe_cast_box::<_, T>(value).unwrap(),
Union::FnPtr(value) => unsafe_try_cast(value).unwrap(),
Union::Variant(value) => (*value).as_box_any().downcast().map(|x| *x).unwrap(),
}
}
/// Get a reference of a specific type to the `Dynamic`.
/// Casting to `Dynamic` just returns a reference to it.
/// Returns `None` if the cast fails.
pub fn downcast_ref<T: Variant + Clone>(&self) -> Option<&T> {
if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
return <dyn Any>::downcast_ref::<T>(self);
}
match &self.0 {
Union::Unit(value) => <dyn Any>::downcast_ref::<T>(value),
Union::Bool(value) => <dyn Any>::downcast_ref::<T>(value),
Union::Str(value) => <dyn Any>::downcast_ref::<T>(value)
.or_else(|| <dyn Any>::downcast_ref::<T>(value.as_ref())),
Union::Char(value) => <dyn Any>::downcast_ref::<T>(value),
Union::Int(value) => <dyn Any>::downcast_ref::<T>(value),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => <dyn Any>::downcast_ref::<T>(value),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => <dyn Any>::downcast_ref::<T>(value.as_ref()),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => <dyn Any>::downcast_ref::<T>(value.as_ref()),
Union::FnPtr(value) => <dyn Any>::downcast_ref::<T>(value),
Union::Variant(value) => value.as_ref().as_ref().as_any().downcast_ref::<T>(),
}
}
/// Get a mutable reference of a specific type to the `Dynamic`.
/// Casting to `Dynamic` just returns a mutable reference to it.
/// Returns `None` if the cast fails.
pub fn downcast_mut<T: Variant + Clone>(&mut self) -> Option<&mut T> {
if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
return <dyn Any>::downcast_mut::<T>(self);
}
match &mut self.0 {
Union::Unit(value) => <dyn Any>::downcast_mut::<T>(value),
Union::Bool(value) => <dyn Any>::downcast_mut::<T>(value),
Union::Str(value) => <dyn Any>::downcast_mut::<T>(value),
Union::Char(value) => <dyn Any>::downcast_mut::<T>(value),
Union::Int(value) => <dyn Any>::downcast_mut::<T>(value),
#[cfg(not(feature = "no_float"))]
Union::Float(value) => <dyn Any>::downcast_mut::<T>(value),
#[cfg(not(feature = "no_index"))]
Union::Array(value) => <dyn Any>::downcast_mut::<T>(value.as_mut()),
#[cfg(not(feature = "no_object"))]
Union::Map(value) => <dyn Any>::downcast_mut::<T>(value.as_mut()),
Union::FnPtr(value) => <dyn Any>::downcast_mut::<T>(value),
Union::Variant(value) => value.as_mut().as_mut_any().downcast_mut::<T>(),
}
}
/// Cast the `Dynamic` as the system integer type `INT` and return it.
/// Returns the name of the actual type if the cast fails.
pub fn as_int(&self) -> Result<INT, &'static str> {
match self.0 {
Union::Int(n) => Ok(n),
_ => Err(self.type_name()),
}
}
/// Cast the `Dynamic` as the system floating-point type `FLOAT` and return it.
/// Returns the name of the actual type if the cast fails.
#[cfg(not(feature = "no_float"))]
pub fn as_float(&self) -> Result<FLOAT, &'static str> {
match self.0 {
Union::Float(n) => Ok(n),
_ => Err(self.type_name()),
}
}
/// Cast the `Dynamic` as a `bool` and return it.
/// Returns the name of the actual type if the cast fails.
pub fn as_bool(&self) -> Result<bool, &'static str> {
match self.0 {
Union::Bool(b) => Ok(b),
_ => Err(self.type_name()),
}
}
/// Cast the `Dynamic` as a `char` and return it.
/// Returns the name of the actual type if the cast fails.
pub fn as_char(&self) -> Result<char, &'static str> {
match self.0 {
Union::Char(n) => Ok(n),
_ => Err(self.type_name()),
}
}
/// Cast the `Dynamic` as a string and return the string slice.
/// Returns the name of the actual type if the cast fails.
pub fn as_str(&self) -> Result<&str, &'static str> {
match &self.0 {
Union::Str(s) => Ok(s),
Union::FnPtr(f) => Ok(f.fn_name()),
_ => Err(self.type_name()),
}
}
/// Convert the `Dynamic` into `String` and return it.
/// Returns the name of the actual type if the cast fails.
pub fn take_string(self) -> Result<String, &'static str> {
self.take_immutable_string()
.map(ImmutableString::into_owned)
}
/// Convert the `Dynamic` into `ImmutableString` and return it.
/// Returns the name of the actual type if the cast fails.
pub(crate) fn take_immutable_string(self) -> Result<ImmutableString, &'static str> {
match self.0 {
Union::Str(s) => Ok(s),
Union::FnPtr(f) => Ok(f.take_fn_name()),
_ => Err(self.type_name()),
}
}
}
impl From<()> for Dynamic {
fn from(value: ()) -> Self {
Self(Union::Unit(value))
}
}
impl From<bool> for Dynamic {
fn from(value: bool) -> Self {
Self(Union::Bool(value))
}
}
impl From<INT> for Dynamic {
fn from(value: INT) -> Self {
Self(Union::Int(value))
}
}
#[cfg(not(feature = "no_float"))]
impl From<FLOAT> for Dynamic {
fn from(value: FLOAT) -> Self {
Self(Union::Float(value))
}
}
impl From<char> for Dynamic {
fn from(value: char) -> Self {
Self(Union::Char(value))
}
}
impl<S: Into<ImmutableString>> From<S> for Dynamic {
fn from(value: S) -> Self {
Self(Union::Str(value.into()))
}
}
#[cfg(not(feature = "no_index"))]
impl<T: Variant + Clone> From<Vec<T>> for Dynamic {
fn from(value: Vec<T>) -> Self {
Self(Union::Array(Box::new(
value.into_iter().map(Dynamic::from).collect(),
)))
}
}
#[cfg(not(feature = "no_index"))]
impl<T: Variant + Clone> From<&[T]> for Dynamic {
fn from(value: &[T]) -> Self {
Self(Union::Array(Box::new(
value.iter().cloned().map(Dynamic::from).collect(),
)))
}
}
#[cfg(not(feature = "no_object"))]
impl<K: Into<ImmutableString>, T: Variant + Clone> From<HashMap<K, T>> for Dynamic {
fn from(value: HashMap<K, T>) -> Self {
Self(Union::Map(Box::new(
value
.into_iter()
.map(|(k, v)| (k.into(), Dynamic::from(v)))
.collect(),
)))
}
}
impl From<FnPtr> for Dynamic {
fn from(value: FnPtr) -> Self {
Self(Union::FnPtr(value))
}
}
/// Private type which ensures that `rhai::Any` and `rhai::AnyExt` can only
/// be implemented by this crate.
#[doc(hidden)]
pub struct _Private;