1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
// This file is part of Substrate.

// Copyright (C) 2017-2022 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::{BlockHash, Config, Pallet};
use codec::{Decode, Encode};
use scale_info::TypeInfo;
use sp_runtime::{
	generic::Era,
	traits::{DispatchInfoOf, SaturatedConversion, SignedExtension},
	transaction_validity::{
		InvalidTransaction, TransactionValidity, TransactionValidityError, ValidTransaction,
	},
};

/// Check for transaction mortality.
///
/// # Transaction Validity
///
/// The extension affects `longevity` of the transaction according to the [`Era`] definition.
#[derive(Encode, Decode, Clone, Eq, PartialEq, TypeInfo)]
#[scale_info(skip_type_params(T))]
pub struct CheckMortality<T: Config + Send + Sync>(pub Era, sp_std::marker::PhantomData<T>);

impl<T: Config + Send + Sync> CheckMortality<T> {
	/// utility constructor. Used only in client/factory code.
	pub fn from(era: Era) -> Self {
		Self(era, sp_std::marker::PhantomData)
	}
}

impl<T: Config + Send + Sync> sp_std::fmt::Debug for CheckMortality<T> {
	#[cfg(feature = "std")]
	fn fmt(&self, f: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
		write!(f, "CheckMortality({:?})", self.0)
	}

	#[cfg(not(feature = "std"))]
	fn fmt(&self, _: &mut sp_std::fmt::Formatter) -> sp_std::fmt::Result {
		Ok(())
	}
}

impl<T: Config + Send + Sync> SignedExtension for CheckMortality<T> {
	type AccountId = T::AccountId;
	type Call = T::Call;
	type AdditionalSigned = T::Hash;
	type Pre = ();
	const IDENTIFIER: &'static str = "CheckMortality";

	fn validate(
		&self,
		_who: &Self::AccountId,
		_call: &Self::Call,
		_info: &DispatchInfoOf<Self::Call>,
		_len: usize,
	) -> TransactionValidity {
		let current_u64 = <Pallet<T>>::block_number().saturated_into::<u64>();
		let valid_till = self.0.death(current_u64);
		Ok(ValidTransaction {
			longevity: valid_till.saturating_sub(current_u64),
			..Default::default()
		})
	}

	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
		let current_u64 = <Pallet<T>>::block_number().saturated_into::<u64>();
		let n = self.0.birth(current_u64).saturated_into::<T::BlockNumber>();
		if !<BlockHash<T>>::contains_key(n) {
			Err(InvalidTransaction::AncientBirthBlock.into())
		} else {
			Ok(<Pallet<T>>::block_hash(n))
		}
	}

	fn pre_dispatch(
		self,
		who: &Self::AccountId,
		call: &Self::Call,
		info: &DispatchInfoOf<Self::Call>,
		len: usize,
	) -> Result<Self::Pre, TransactionValidityError> {
		self.validate(who, call, info, len).map(|_| ())
	}
}

#[cfg(test)]
mod tests {
	use super::*;
	use crate::mock::{new_test_ext, System, Test, CALL};
	use frame_support::weights::{DispatchClass, DispatchInfo, Pays, Weight};
	use sp_core::H256;

	#[test]
	fn signed_ext_check_era_should_work() {
		new_test_ext().execute_with(|| {
			// future
			assert_eq!(
				CheckMortality::<Test>::from(Era::mortal(4, 2))
					.additional_signed()
					.err()
					.unwrap(),
				InvalidTransaction::AncientBirthBlock.into(),
			);

			// correct
			System::set_block_number(13);
			<BlockHash<Test>>::insert(12, H256::repeat_byte(1));
			assert!(CheckMortality::<Test>::from(Era::mortal(4, 12)).additional_signed().is_ok());
		})
	}

	#[test]
	fn signed_ext_check_era_should_change_longevity() {
		new_test_ext().execute_with(|| {
			let normal = DispatchInfo {
				weight: Weight::from_ref_time(100),
				class: DispatchClass::Normal,
				pays_fee: Pays::Yes,
			};
			let len = 0_usize;
			let ext = (
				crate::CheckWeight::<Test>::new(),
				CheckMortality::<Test>::from(Era::mortal(16, 256)),
			);
			System::set_block_number(17);
			<BlockHash<Test>>::insert(16, H256::repeat_byte(1));

			assert_eq!(ext.validate(&1, CALL, &normal, len).unwrap().longevity, 15);
		})
	}
}