oc_wasm_helpers/
error.rs

1use minicbor::{Decode, Decoder};
2
3/// A successful method call result, or an error value decoded from an array of return values whose
4/// first entry is null and whose second entry is a string message.
5///
6/// This is a common convention used by various OpenComputers component APIs to report some (but
7/// not all) errors.
8///
9/// The `'buffer` parameter is the lifetime of the buffer from which the error string is decoded.
10/// The `T` parameter is the type to decode if the call was successful.
11#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
12pub enum NullAndStringOr<'buffer, T> {
13	Ok(T),
14	Err(&'buffer str),
15}
16
17impl<'buffer, Context, T: Decode<'buffer, Context>> Decode<'buffer, Context>
18	for NullAndStringOr<'buffer, T>
19{
20	fn decode(
21		d: &mut Decoder<'buffer>,
22		context: &mut Context,
23	) -> Result<Self, minicbor::decode::Error> {
24		let mut p = d.probe();
25		let is_error = if let Some(length) = p.array()? {
26			if length == 2 {
27				p.datatype()? == minicbor::data::Type::Null
28			} else {
29				false
30			}
31		} else {
32			false
33		};
34		if is_error {
35			d.array()?;
36			d.skip()?;
37			Ok(Self::Err(d.str()?))
38		} else {
39			Ok(Self::Ok(T::decode(d, context)?))
40		}
41	}
42}
43
44/// An error returned when converting an invalid value to an enumeration.
45#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
46pub struct TryFromInt;
47
48impl core::fmt::Display for TryFromInt {
49	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> Result<(), core::fmt::Error> {
50		"invalid value".fmt(f)
51	}
52}
53
54#[cfg(feature = "std")]
55impl std::error::Error for TryFromInt {}
oc_wasm_helpers/error.rs

oc_wasm_helpers/
error.rs
