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

// Copyright 2021 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Polkadot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

//! A module that is responsible for migration of storage.

use crate::{Config, Pallet, Store};
use frame_support::{pallet_prelude::*, traits::StorageVersion, weights::Weight};

/// The current storage version.
pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(1);

/// Migrates the pallet storage to the most recent version, checking and setting the
/// `StorageVersion`.
pub fn migrate_to_latest<T: Config>() -> Weight {
	let mut weight = Weight::zero();

	if StorageVersion::get::<Pallet<T>>() == 0 {
		weight += migrate_to_v1::<T>();
		StorageVersion::new(1).put::<Pallet<T>>();
	}

	weight
}

mod v0 {
	use super::*;
	use codec::{Decode, Encode};

	#[derive(Encode, Decode, Debug)]
	pub struct QueueConfigData {
		pub suspend_threshold: u32,
		pub drop_threshold: u32,
		pub resume_threshold: u32,
		pub threshold_weight: Weight,
		pub weight_restrict_decay: Weight,
	}

	impl Default for QueueConfigData {
		fn default() -> Self {
			QueueConfigData {
				suspend_threshold: 2,
				drop_threshold: 5,
				resume_threshold: 1,
				threshold_weight: Weight::from_ref_time(100_000),
				weight_restrict_decay: Weight::from_ref_time(2),
			}
		}
	}
}

/// Migrates `QueueConfigData` from v0 (without the `xcmp_max_individual_weight` field) to v1 (with
/// max individual weight).
/// Uses the `Default` implementation of `QueueConfigData` to choose a value for
/// `xcmp_max_individual_weight`.
///
/// NOTE: Only use this function if you know what you're doing. Default to using
/// `migrate_to_latest`.
pub fn migrate_to_v1<T: Config>() -> Weight {
	let translate = |pre: v0::QueueConfigData| -> super::QueueConfigData {
		super::QueueConfigData {
			suspend_threshold: pre.suspend_threshold,
			drop_threshold: pre.drop_threshold,
			resume_threshold: pre.resume_threshold,
			threshold_weight: pre.threshold_weight,
			weight_restrict_decay: pre.weight_restrict_decay,
			xcmp_max_individual_weight: super::QueueConfigData::default()
				.xcmp_max_individual_weight,
		}
	};

	if let Err(_) = <Pallet<T> as Store>::QueueConfig::translate(|pre| pre.map(translate)) {
		log::error!(
			target: super::LOG_TARGET,
			"unexpected error when performing translation of the QueueConfig type during storage upgrade to v1"
		);
	}

	T::DbWeight::get().reads_writes(1, 1)
}

#[cfg(test)]
mod tests {
	use super::*;
	use crate::mock::{new_test_ext, Test};

	#[test]
	fn test_migration_to_v1() {
		let v0 = v0::QueueConfigData {
			suspend_threshold: 5,
			drop_threshold: 12,
			resume_threshold: 3,
			threshold_weight: Weight::from_ref_time(333_333),
			weight_restrict_decay: Weight::from_ref_time(1),
		};

		new_test_ext().execute_with(|| {
			// Put the v0 version in the state
			frame_support::storage::unhashed::put_raw(
				&crate::QueueConfig::<Test>::hashed_key(),
				&v0.encode(),
			);

			migrate_to_v1::<Test>();

			let v1 = crate::QueueConfig::<Test>::get();

			assert_eq!(v0.suspend_threshold, v1.suspend_threshold);
			assert_eq!(v0.drop_threshold, v1.drop_threshold);
			assert_eq!(v0.resume_threshold, v1.resume_threshold);
			assert_eq!(v0.threshold_weight, v1.threshold_weight);
			assert_eq!(v0.weight_restrict_decay, v1.weight_restrict_decay);
			assert_eq!(v1.xcmp_max_individual_weight, Weight::from_ref_time(20_000_000_000));
		});
	}
}