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| 1 | +// Copyright (C) 2022 Subspace Labs, Inc. |
| 2 | +// SPDX-License-Identifier: Apache-2.0 |
| 3 | + |
| 4 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | +// you may not use this file except in compliance with the License. |
| 6 | +// You may obtain a copy of the License at |
| 7 | +// |
| 8 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | +// |
| 10 | +// Unless required by applicable law or agreed to in writing, software |
| 11 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | +// See the License for the specific language governing permissions and |
| 14 | +// limitations under the License. |
| 15 | + |
| 16 | +//! Pallet that provides necessary Leaf data for MMR. |
| 17 | +
|
| 18 | +#![cfg_attr(not(feature = "std"), no_std)] |
| 19 | +#![feature(associated_type_bounds)] |
| 20 | + |
| 21 | +use frame_system::pallet_prelude::BlockNumberFor; |
| 22 | +use log::error; |
| 23 | +pub use pallet::*; |
| 24 | +use sp_mmr_primitives::{LeafDataProvider, OnNewRoot}; |
| 25 | +use sp_runtime::traits::One; |
| 26 | +use sp_runtime::{DigestItem, Saturating}; |
| 27 | +use sp_subspace_mmr::subspace_mmr_runtime_interface::get_mmr_leaf_data; |
| 28 | +use sp_subspace_mmr::{LeafDataV0, MmrDigest, MmrLeaf}; |
| 29 | + |
| 30 | +#[frame_support::pallet] |
| 31 | +mod pallet { |
| 32 | + use frame_support::Parameter; |
| 33 | + use sp_core::H256; |
| 34 | + |
| 35 | + #[pallet::pallet] |
| 36 | + pub struct Pallet<T>(_); |
| 37 | + |
| 38 | + #[pallet::config] |
| 39 | + pub trait Config: frame_system::Config<Hash: Into<H256> + From<H256>> { |
| 40 | + type MmrRootHash: Parameter + Copy; |
| 41 | + } |
| 42 | +} |
| 43 | + |
| 44 | +impl<T: Config> OnNewRoot<T::MmrRootHash> for Pallet<T> { |
| 45 | + fn on_new_root(root: &T::MmrRootHash) { |
| 46 | + let digest = DigestItem::new_mmr_root(*root); |
| 47 | + <frame_system::Pallet<T>>::deposit_log(digest); |
| 48 | + } |
| 49 | +} |
| 50 | + |
| 51 | +impl<T: Config> LeafDataProvider for Pallet<T> { |
| 52 | + type LeafData = MmrLeaf<BlockNumberFor<T>, T::Hash>; |
| 53 | + |
| 54 | + fn leaf_data() -> Self::LeafData { |
| 55 | + let block_number = frame_system::Pallet::<T>::block_number().saturating_sub(One::one()); |
| 56 | + let block_hash = frame_system::Pallet::<T>::parent_hash(); |
| 57 | + // unfortunately, we Leaf data provider trait expects the impl to be infallible |
| 58 | + // but our host function might fail for any reason but practically shouldn't since |
| 59 | + // we are querying the immediate parent block |
| 60 | + // We will just log an error in case of such ever happening |
| 61 | + let leaf_data = get_mmr_leaf_data(block_hash.into()).unwrap_or_else(|| { |
| 62 | + error!(target: "runtime::subspace_mmr", "Failed to fetch leaf data for Block hash{block_hash:?}"); |
| 63 | + Default::default() |
| 64 | + }); |
| 65 | + MmrLeaf::V0(LeafDataV0 { |
| 66 | + block_number, |
| 67 | + block_hash, |
| 68 | + state_root: leaf_data.state_root.into(), |
| 69 | + extrinsics_root: leaf_data.extrinsics_root.into(), |
| 70 | + }) |
| 71 | + } |
| 72 | +} |
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