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pezkuwi-subxt/polkadot/test-parachains/adder/src/lib.rs
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Gav Wood 84748fccd3 Bring runtime API up to date with Substrate master (#17)
* Fixups for 646

* Fixes for API

* For for #678

* Fix runtime

* Update and build

* Tests build

* Fix tests
2018-09-12 19:36:33 +02:00

80 lines
2.2 KiB
Rust

// Copyright 2017 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/>.
//! Basic parachain that adds a number as part of its state.
#![no_std]
#[macro_use]
extern crate parity_codec_derive;
extern crate polkadot_parachain as parachain;
extern crate tiny_keccak;
use parachain::codec::{self, Encode};
/// Head data for this parachain.
#[derive(Default, Clone, Hash, Eq, PartialEq, Encode, Decode)]
pub struct HeadData {
/// Block number
pub number: u64,
/// parent block keccak256
pub parent_hash: [u8; 32],
/// hash of post-execution state.
pub post_state: [u8; 32],
}
impl HeadData {
pub fn hash(&self) -> [u8; 32] {
::tiny_keccak::keccak256(&self.encode())
}
}
/// Block data for this parachain.
#[derive(Default, Clone, Encode, Decode)]
pub struct BlockData {
/// State to begin from.
pub state: u64,
/// Amount to add (overflowing)
pub add: u64,
}
pub fn hash_state(state: u64) -> [u8; 32] {
::tiny_keccak::keccak256(state.encode().as_slice())
}
/// Start state mismatched with parent header's state hash.
#[derive(Debug)]
pub struct StateMismatch;
/// Execute a block body on top of given parent head, producing new parent head
/// if valid.
pub fn execute(parent_hash: [u8; 32], parent_head: HeadData, block_data: &BlockData) -> Result<HeadData, StateMismatch> {
debug_assert_eq!(parent_hash, parent_head.hash());
if hash_state(block_data.state) != parent_head.post_state {
return Err(StateMismatch);
}
let new_state = block_data.state.overflowing_add(block_data.add).0;
Ok(HeadData {
number: parent_head.number + 1,
parent_hash,
post_state: hash_state(new_state),
})
}