1// This file is part of Substrate.
23// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
56// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
1718//! Traits for describing and constraining pallet error types.
19use codec::{Compact, Decode, Encode};
20use core::marker::PhantomData;
2122/// Trait indicating that the implementing type is going to be included as a field in a variant of
23/// the `#[pallet::error]` enum type.
24///
25/// ## Notes
26///
27/// The pallet error enum has a maximum encoded size as defined by
28/// [`frame_support::MAX_MODULE_ERROR_ENCODED_SIZE`]. If the pallet error type exceeds this size
29/// limit, a static assertion during compilation will fail. The compilation error will be in the
30/// format of `error[E0080]: evaluation of constant value failed` due to the usage of
31/// const assertions.
32pub trait PalletError: Encode + Decode {
33/// The maximum encoded size for the implementing type.
34 ///
35 /// This will be used to check whether the pallet error type is less than or equal to
36 /// [`frame_support::MAX_MODULE_ERROR_ENCODED_SIZE`], and if it is, a compilation error will be
37 /// thrown.
38const MAX_ENCODED_SIZE: usize;
39}
4041macro_rules! impl_for_types {
42 (size: $size:expr, $($typ:ty),+) => {
43 $(
44impl PalletError for $typ {
45const MAX_ENCODED_SIZE: usize = $size;
46 }
47 )+
48 };
49}
5051impl_for_types!(size: 0, (), crate::Never);
52impl_for_types!(size: 1, u8, i8, bool);
53impl_for_types!(size: 2, u16, i16, Compact<u8>);
54impl_for_types!(size: 4, u32, i32, Compact<u16>);
55impl_for_types!(size: 5, Compact<u32>);
56impl_for_types!(size: 8, u64, i64);
57impl_for_types!(size: 9, Compact<u64>);
58// Contains a u64 for secs and u32 for nanos, hence 12 bytes
59impl_for_types!(size: 12, core::time::Duration);
60impl_for_types!(size: 16, u128, i128);
61impl_for_types!(size: 17, Compact<u128>);
6263impl<T> PalletError for PhantomData<T> {
64const MAX_ENCODED_SIZE: usize = 0;
65}
6667impl<T: PalletError> PalletError for core::ops::Range<T> {
68const MAX_ENCODED_SIZE: usize = T::MAX_ENCODED_SIZE.saturating_mul(2);
69}
7071impl<T: PalletError, const N: usize> PalletError for [T; N] {
72const MAX_ENCODED_SIZE: usize = T::MAX_ENCODED_SIZE.saturating_mul(N);
73}
7475impl<T: PalletError> PalletError for Option<T> {
76const MAX_ENCODED_SIZE: usize = T::MAX_ENCODED_SIZE.saturating_add(1);
77}
7879impl<T: PalletError, E: PalletError> PalletError for Result<T, E> {
80const MAX_ENCODED_SIZE: usize = if T::MAX_ENCODED_SIZE > E::MAX_ENCODED_SIZE {
81 T::MAX_ENCODED_SIZE
82 } else {
83 E::MAX_ENCODED_SIZE
84 }
85 .saturating_add(1);
86}
8788#[impl_trait_for_tuples::impl_for_tuples(1, 18)]
89impl PalletError for Tuple {
90const MAX_ENCODED_SIZE: usize = {
91let mut size = 0_usize;
92for_tuples!( #(size = size.saturating_add(Tuple::MAX_ENCODED_SIZE);)* );
93 size
94 };
95}