wasmi/src/global.rs

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2018-01-17 15:32:33 +00:00
use std::rc::Rc;
use std::cell::Cell;
use parity_wasm::elements::ValueType;
use value::RuntimeValue;
use Error;
#[derive(Clone, Debug)]
pub struct GlobalRef(Rc<GlobalInstance>);
impl ::std::ops::Deref for GlobalRef {
type Target = GlobalInstance;
fn deref(&self) -> &GlobalInstance {
&self.0
}
}
#[derive(Debug)]
pub struct GlobalInstance {
val: Cell<RuntimeValue>,
mutable: bool,
}
impl GlobalInstance {
pub fn alloc(val: RuntimeValue, mutable: bool) -> GlobalRef {
let global = GlobalInstance::new(val, mutable);
GlobalRef(Rc::new(global))
}
fn new(val: RuntimeValue, mutable: bool) -> GlobalInstance {
GlobalInstance {
val: Cell::new(val),
mutable,
}
}
pub fn set(&self, val: RuntimeValue) -> Result<(), Error> {
if !self.mutable {
return Err(Error::Global("Attempt to change an immutable variable".into()));
}
if self.value_type() != val.value_type() {
return Err(Error::Global("Attempt to change variable type".into()));
}
self.val.set(val);
Ok(())
}
pub fn get(&self) -> RuntimeValue {
self.val.get()
}
pub fn is_mutable(&self) -> bool {
self.mutable
}
pub fn value_type(&self) -> ValueType {
self.val.get().value_type()
}
}