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use runtime::{Class, Object, Sel};
use {Encode, EncodeArguments};
use super::MessageError;
pub fn verify_message_signature<A, R>(cls: &Class, sel: Sel)
-> Result<(), MessageError>
where A: EncodeArguments, R: Encode {
let method = match cls.instance_method(sel) {
Some(method) => method,
None => return Err(MessageError(
format!("Method {:?} not found on class {:?}",
sel, cls)
)),
};
let ret = R::encode();
let expected_ret = method.return_type();
if ret != expected_ret {
return Err(MessageError(
format!("Return type code {:?} does not match expected {:?} for method {:?}",
ret, expected_ret, method.name())
));
}
let self_and_cmd = [<*mut Object>::encode(), Sel::encode()];
let args = A::encodings();
let args = args.as_ref();
let count = self_and_cmd.len() + args.len();
let expected_count = method.arguments_count();
if count != expected_count {
return Err(MessageError(
format!("Method {:?} accepts {} arguments, but {} were given",
method.name(), expected_count, count)
));
}
for (i, arg) in self_and_cmd.iter().chain(args).enumerate() {
let expected = method.argument_type(i).unwrap();
if *arg != expected {
return Err(MessageError(
format!("Method {:?} expected argument at index {} with type code {:?} but was given {:?}",
method.name(), i, expected, arg)
));
}
}
Ok(())
}