Starting to mess with promises

Going to want async IO, I think. And it's a fun detail that I guess
I'm in charge of deciding when to run promise completion functions. :D

oden-js/src/value.rs

@@ -310,14 +310,16 @@ impl ValueRef {
         Ok(result)
     }
 
-    pub fn call(&self, ctx: &ContextRef) -> Result<Value> {
+    pub fn call(&self, ctx: &ContextRef, args: &[&ValueRef]) -> Result<Value> {
+        // TODO: There *must* be a way to avoid this allocation.
+        let mut args: Vec<sys::JSValue> = args.iter().map(|v| v.val).collect();
         unsafe {
             ctx.check_exception(sys::JS_Call(
                 ctx.ctx,
                 self.val,
                 sys::JS_MakeUndefined(),
-                0,
-                std::ptr::null_mut(),
+                args.len() as i32,
+                args.as_mut_ptr(),
             ))
         }
     }
@@ -345,9 +347,16 @@ impl Value {
     /// the runtime of the specified context, if not the context itself. This
     /// function makes no attempt to validate this.
     pub(crate) fn from_raw(val: sys::JSValue, ctx: &ContextRef) -> Self {
+        Value::from_raw_rt(
+            val,
+            Runtime::from_raw(unsafe { sys::JS_GetRuntime(ctx.ctx) }),
+        )
+    }
+
+    pub(crate) fn from_raw_rt(val: sys::JSValue, rt: Runtime) -> Self {
         Value {
             value: ValueRef::from_raw(val),
-            rt: Runtime::from_raw(unsafe { sys::JS_GetRuntime(ctx.ctx) }),
+            rt,
         }
     }
 
@@ -394,6 +403,15 @@ impl fmt::Debug for Value {
     }
 }
 
+impl Clone for Value {
+    fn clone(&self) -> Self {
+        unsafe {
+            sys::JS_DupValueRT(self.rt.rt, self.val);
+        }
+        Value::from_raw_rt(self.val, self.rt.clone())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;