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use crate::r#ref::ExternRef;
use crate::store::StoreOpaque;
use crate::{AsContextMut, Func, ValType};
use anyhow::{bail, Result};
use std::ptr;
use wasmtime_runtime::TableElement;
pub use wasmtime_runtime::ValRaw;
/// Possible runtime values that a WebAssembly module can either consume or
/// produce.
#[derive(Debug, Clone)]
pub enum Val {
// NB: the ordering here is intended to match the ordering in
// `ValType` to improve codegen when learning the type of a value.
/// A 32-bit integer
I32(i32),
/// A 64-bit integer
I64(i64),
/// A 32-bit float.
///
/// Note that the raw bits of the float are stored here, and you can use
/// `f32::from_bits` to create an `f32` value.
F32(u32),
/// A 64-bit float.
///
/// Note that the raw bits of the float are stored here, and you can use
/// `f64::from_bits` to create an `f64` value.
F64(u64),
/// A 128-bit number
V128(u128),
/// A first-class reference to a WebAssembly function.
///
/// `FuncRef(None)` is the null function reference, created by `ref.null
/// func` in Wasm.
FuncRef(Option<Func>),
/// An `externref` value which can hold opaque data to the Wasm instance
/// itself.
///
/// `ExternRef(None)` is the null external reference, created by `ref.null
/// extern` in Wasm.
ExternRef(Option<ExternRef>),
}
macro_rules! accessors {
($bind:ident $(($variant:ident($ty:ty) $get:ident $unwrap:ident $cvt:expr))*) => ($(
/// Attempt to access the underlying value of this `Val`, returning
/// `None` if it is not the correct type.
#[inline]
pub fn $get(&self) -> Option<$ty> {
if let Val::$variant($bind) = self {
Some($cvt)
} else {
None
}
}
/// Returns the underlying value of this `Val`, panicking if it's the
/// wrong type.
///
/// # Panics
///
/// Panics if `self` is not of the right type.
#[inline]
pub fn $unwrap(&self) -> $ty {
self.$get().expect(concat!("expected ", stringify!($ty)))
}
)*)
}
impl Val {
/// Returns a null `externref` value.
#[inline]
pub fn null() -> Val {
Val::ExternRef(None)
}
/// Returns the corresponding [`ValType`] for this `Val`.
#[inline]
pub fn ty(&self) -> ValType {
match self {
Val::I32(_) => ValType::I32,
Val::I64(_) => ValType::I64,
Val::F32(_) => ValType::F32,
Val::F64(_) => ValType::F64,
Val::ExternRef(_) => ValType::ExternRef,
Val::FuncRef(_) => ValType::FuncRef,
Val::V128(_) => ValType::V128,
}
}
/// Convenience method to convert this [`Val`] into a [`ValRaw`].
///
/// # Unsafety
///
/// This method is unsafe for the reasons that [`ExternRef::to_raw`] and
/// [`Func::to_raw`] are unsafe.
pub unsafe fn to_raw(&self, store: impl AsContextMut) -> ValRaw {
match self {
Val::I32(i) => ValRaw::i32(*i),
Val::I64(i) => ValRaw::i64(*i),
Val::F32(u) => ValRaw::f32(*u),
Val::F64(u) => ValRaw::f64(*u),
Val::V128(b) => ValRaw::v128(*b),
Val::ExternRef(e) => {
let externref = match e {
Some(e) => e.to_raw(store),
None => 0,
};
ValRaw::externref(externref)
}
Val::FuncRef(f) => {
let funcref = match f {
Some(f) => f.to_raw(store),
None => 0,
};
ValRaw::funcref(funcref)
}
}
}
/// Convenience method to convert a [`ValRaw`] into a [`Val`].
///
/// # Unsafety
///
/// This method is unsafe for the reasons that [`ExternRef::from_raw`] and
/// [`Func::from_raw`] are unsafe. Additionaly there's no guarantee
/// otherwise that `raw` should have the type `ty` specified.
pub unsafe fn from_raw(store: impl AsContextMut, raw: ValRaw, ty: ValType) -> Val {
match ty {
ValType::I32 => Val::I32(raw.get_i32()),
ValType::I64 => Val::I64(raw.get_i64()),
ValType::F32 => Val::F32(raw.get_f32()),
ValType::F64 => Val::F64(raw.get_f64()),
ValType::V128 => Val::V128(raw.get_v128()),
ValType::ExternRef => Val::ExternRef(ExternRef::from_raw(raw.get_externref())),
ValType::FuncRef => Val::FuncRef(Func::from_raw(store, raw.get_funcref())),
}
}
accessors! {
e
(I32(i32) i32 unwrap_i32 *e)
(I64(i64) i64 unwrap_i64 *e)
(F32(f32) f32 unwrap_f32 f32::from_bits(*e))
(F64(f64) f64 unwrap_f64 f64::from_bits(*e))
(FuncRef(Option<&Func>) funcref unwrap_funcref e.as_ref())
(V128(u128) v128 unwrap_v128 *e)
}
/// Attempt to access the underlying `externref` value of this `Val`.
///
/// If this is not an `externref`, then `None` is returned.
///
/// If this is a null `externref`, then `Some(None)` is returned.
///
/// If this is a non-null `externref`, then `Some(Some(..))` is returned.
#[inline]
pub fn externref(&self) -> Option<Option<ExternRef>> {
match self {
Val::ExternRef(e) => Some(e.clone()),
_ => None,
}
}
/// Returns the underlying `externref` value of this `Val`, panicking if it's the
/// wrong type.
///
/// If this is a null `externref`, then `None` is returned.
///
/// If this is a non-null `externref`, then `Some(..)` is returned.
///
/// # Panics
///
/// Panics if `self` is not a (nullable) `externref`.
#[inline]
pub fn unwrap_externref(&self) -> Option<ExternRef> {
self.externref().expect("expected externref")
}
pub(crate) fn into_table_element(
self,
store: &mut StoreOpaque,
ty: ValType,
) -> Result<TableElement> {
match (self, ty) {
(Val::FuncRef(Some(f)), ValType::FuncRef) => {
if !f.comes_from_same_store(store) {
bail!("cross-`Store` values are not supported in tables");
}
Ok(TableElement::FuncRef(
f.caller_checked_anyfunc(store).as_ptr(),
))
}
(Val::FuncRef(None), ValType::FuncRef) => Ok(TableElement::FuncRef(ptr::null_mut())),
(Val::ExternRef(Some(x)), ValType::ExternRef) => {
Ok(TableElement::ExternRef(Some(x.inner)))
}
(Val::ExternRef(None), ValType::ExternRef) => Ok(TableElement::ExternRef(None)),
_ => bail!("value does not match table element type"),
}
}
#[inline]
pub(crate) fn comes_from_same_store(&self, store: &StoreOpaque) -> bool {
match self {
Val::FuncRef(Some(f)) => f.comes_from_same_store(store),
Val::FuncRef(None) => true,
// Integers, floats, vectors, and `externref`s have no association
// with any particular store, so they're always considered as "yes I
// came from that store",
Val::I32(_)
| Val::I64(_)
| Val::F32(_)
| Val::F64(_)
| Val::V128(_)
| Val::ExternRef(_) => true,
}
}
}
impl From<i32> for Val {
#[inline]
fn from(val: i32) -> Val {
Val::I32(val)
}
}
impl From<i64> for Val {
#[inline]
fn from(val: i64) -> Val {
Val::I64(val)
}
}
impl From<f32> for Val {
#[inline]
fn from(val: f32) -> Val {
Val::F32(val.to_bits())
}
}
impl From<f64> for Val {
#[inline]
fn from(val: f64) -> Val {
Val::F64(val.to_bits())
}
}
impl From<ExternRef> for Val {
#[inline]
fn from(val: ExternRef) -> Val {
Val::ExternRef(Some(val))
}
}
impl From<Option<ExternRef>> for Val {
#[inline]
fn from(val: Option<ExternRef>) -> Val {
Val::ExternRef(val)
}
}
impl From<Option<Func>> for Val {
#[inline]
fn from(val: Option<Func>) -> Val {
Val::FuncRef(val)
}
}
impl From<Func> for Val {
#[inline]
fn from(val: Func) -> Val {
Val::FuncRef(Some(val))
}
}
impl From<u128> for Val {
#[inline]
fn from(val: u128) -> Val {
Val::V128(val)
}
}