bp_runtime/
storage_types.rs

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1// Copyright (C) Parity Technologies (UK) Ltd.
2// This file is part of Parity Bridges Common.
3
4// Parity Bridges Common is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8
9// Parity Bridges Common is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License
15// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
16
17//! Wrapper for a runtime storage value that checks if value exceeds given maximum
18//! during conversion.
19
20use codec::{Decode, Encode, MaxEncodedLen};
21use frame_support::traits::Get;
22use scale_info::{Type, TypeInfo};
23use sp_runtime::RuntimeDebug;
24use sp_std::{marker::PhantomData, ops::Deref};
25
26/// Error that is returned when the value size exceeds maximal configured size.
27#[derive(RuntimeDebug)]
28pub struct MaximalSizeExceededError {
29	/// Size of the value.
30	pub value_size: usize,
31	/// Maximal configured size.
32	pub maximal_size: usize,
33}
34
35/// A bounded runtime storage value.
36#[derive(Clone, Decode, Encode, Eq, PartialEq)]
37pub struct BoundedStorageValue<B, V> {
38	value: V,
39	_phantom: PhantomData<B>,
40}
41
42impl<B, V: sp_std::fmt::Debug> sp_std::fmt::Debug for BoundedStorageValue<B, V> {
43	fn fmt(&self, fmt: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
44		self.value.fmt(fmt)
45	}
46}
47
48impl<B: Get<u32>, V: Encode> BoundedStorageValue<B, V> {
49	/// Construct `BoundedStorageValue` from the underlying `value` with all required checks.
50	///
51	/// Returns error if value size exceeds given bounds.
52	pub fn try_from_inner(value: V) -> Result<Self, MaximalSizeExceededError> {
53		// this conversion is heavy (since we do encoding here), so we may want to optimize it later
54		// (e.g. by introducing custom Encode implementation, and turning `BoundedStorageValue` into
55		// `enum BoundedStorageValue { Decoded(V), Encoded(Vec<u8>) }`)
56		let value_size = value.encoded_size();
57		let maximal_size = B::get() as usize;
58		if value_size > maximal_size {
59			Err(MaximalSizeExceededError { value_size, maximal_size })
60		} else {
61			Ok(BoundedStorageValue { value, _phantom: Default::default() })
62		}
63	}
64
65	/// Convert into the inner type
66	pub fn into_inner(self) -> V {
67		self.value
68	}
69}
70
71impl<B, V> Deref for BoundedStorageValue<B, V> {
72	type Target = V;
73
74	fn deref(&self) -> &Self::Target {
75		&self.value
76	}
77}
78
79impl<B: 'static, V: TypeInfo + 'static> TypeInfo for BoundedStorageValue<B, V> {
80	type Identity = Self;
81
82	fn type_info() -> Type {
83		V::type_info()
84	}
85}
86
87impl<B: Get<u32>, V: Encode> MaxEncodedLen for BoundedStorageValue<B, V> {
88	fn max_encoded_len() -> usize {
89		B::get() as usize
90	}
91}
bp_runtime/storage_types.rs

bp_runtime/
storage_types.rs
