d1b1500d19
This commit adds a `wasmtime-rust` crate to the `misc` folder next to the previously added Python extension. The intention is that this showcases loading a WebAssembly file natively in Rust and how with an attribute macro it can feel lightweight in terms of boilerplate. The macro itself is pretty non-featureful today beyond the bare bones to get anything working, but there's all sorts of possibilities like JIT-compiled entry stubs we could eventually do with all the type information!
67 lines
1.4 KiB
Rust
67 lines
1.4 KiB
Rust
use std::convert::TryFrom;
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use std::fmt;
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/// The set of all possible WebAssembly Interface Types
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#[derive(Debug, Clone)]
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#[allow(missing_docs)]
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pub enum Value {
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String(String),
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I32(i32),
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U32(u32),
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I64(i64),
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U64(u64),
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F32(f32),
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F64(f64),
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}
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macro_rules! from {
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($($a:ident => $b:ident,)*) => ($(
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impl From<$a> for Value {
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fn from(val: $a) -> Value {
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Value::$b(val)
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}
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}
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impl TryFrom<Value> for $a {
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type Error = failure::Error;
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fn try_from(val: Value) -> Result<$a, Self::Error> {
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match val {
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Value::$b(v) => Ok(v),
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v => failure::bail!("cannot convert {:?} to {}", v, stringify!($a)),
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}
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}
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}
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)*)
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}
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from! {
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String => String,
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i32 => I32,
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u32 => U32,
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i64 => I64,
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u64 => U64,
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f32 => F32,
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f64 => F64,
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}
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impl<'a> From<&'a str> for Value {
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fn from(x: &'a str) -> Value {
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x.to_string().into()
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}
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}
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impl fmt::Display for Value {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match self {
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Value::String(s) => s.fmt(f),
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Value::I32(s) => s.fmt(f),
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Value::U32(s) => s.fmt(f),
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Value::I64(s) => s.fmt(f),
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Value::U64(s) => s.fmt(f),
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Value::F32(s) => s.fmt(f),
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Value::F64(s) => s.fmt(f),
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}
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}
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}
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