sp_session/
lib.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// 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.
17
18//! Substrate core types around sessions.
19
20#![cfg_attr(not(feature = "std"), no_std)]
21
22extern crate alloc;
23
24use codec::{Decode, Encode};
25
26#[cfg(feature = "std")]
27use sp_api::ProvideRuntimeApi;
28#[cfg(feature = "std")]
29use sp_runtime::traits::Block as BlockT;
30
31use alloc::vec::Vec;
32use sp_core::RuntimeDebug;
33use sp_staking::SessionIndex;
34
35pub mod runtime_api;
36pub use runtime_api::*;
37
38/// Number of validators in a given session.
39pub type ValidatorCount = u32;
40
41/// Proof of membership of a specific key in a given session.
42#[derive(Encode, Decode, Clone, Eq, PartialEq, Default, RuntimeDebug, scale_info::TypeInfo)]
43pub struct MembershipProof {
44	/// The session index on which the specific key is a member.
45	pub session: SessionIndex,
46	/// Trie nodes of a merkle proof of session membership.
47	pub trie_nodes: Vec<Vec<u8>>,
48	/// The validator count of the session on which the specific key is a member.
49	pub validator_count: ValidatorCount,
50}
51
52/// A utility trait to get a session number. This is implemented for
53/// `MembershipProof` below to fetch the session number the given session
54/// membership proof is for. It is useful when we need to deal with key owner
55/// proofs generically (i.e. just typing against the `KeyOwnerProofSystem`
56/// trait) but still restrict their capabilities.
57pub trait GetSessionNumber {
58	fn session(&self) -> SessionIndex;
59}
60
61/// A utility trait to get the validator count of a given session. This is
62/// implemented for `MembershipProof` below and fetches the number of validators
63/// in the session the membership proof is for. It is useful when we need to
64/// deal with key owner proofs generically (i.e. just typing against the
65/// `KeyOwnerProofSystem` trait) but still restrict their capabilities.
66pub trait GetValidatorCount {
67	fn validator_count(&self) -> ValidatorCount;
68}
69
70impl GetSessionNumber for sp_core::Void {
71	fn session(&self) -> SessionIndex {
72		Default::default()
73	}
74}
75
76impl GetValidatorCount for sp_core::Void {
77	fn validator_count(&self) -> ValidatorCount {
78		Default::default()
79	}
80}
81
82impl GetSessionNumber for MembershipProof {
83	fn session(&self) -> SessionIndex {
84		self.session
85	}
86}
87
88impl GetValidatorCount for MembershipProof {
89	fn validator_count(&self) -> ValidatorCount {
90		self.validator_count
91	}
92}
93
94/// Generate the initial session keys with the given seeds, at the given block and store them in
95/// the client's keystore.
96#[cfg(feature = "std")]
97pub fn generate_initial_session_keys<Block, T>(
98	client: std::sync::Arc<T>,
99	at: Block::Hash,
100	seeds: Vec<String>,
101	keystore: sp_keystore::KeystorePtr,
102) -> Result<(), sp_api::ApiError>
103where
104	Block: BlockT,
105	T: ProvideRuntimeApi<Block>,
106	T::Api: SessionKeys<Block>,
107{
108	use sp_api::ApiExt;
109
110	if seeds.is_empty() {
111		return Ok(())
112	}
113
114	let mut runtime_api = client.runtime_api();
115
116	runtime_api.register_extension(sp_keystore::KeystoreExt::from(keystore));
117
118	for seed in seeds {
119		runtime_api.generate_session_keys(at, Some(seed.as_bytes().to_vec()))?;
120	}
121
122	Ok(())
123}
sp_session/lib.rs

sp_session/
lib.rs
