2019-01-07 11:33:07 +01:00
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// Copyright 2015-2019 Parity Technologies (UK) Ltd.
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// This file is part of Parity Ethereum.
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2017-09-26 14:19:08 +02:00
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2019-01-07 11:33:07 +01:00
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// Parity Ethereum is free software: you can redistribute it and/or modify
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2017-09-26 14:19:08 +02:00
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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2019-01-07 11:33:07 +01:00
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// Parity Ethereum is distributed in the hope that it will be useful,
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2017-09-26 14:19:08 +02:00
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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2019-01-07 11:33:07 +01:00
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// along with Parity Ethereum. If not, see <http://www.gnu.org/licenses/>.
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2017-09-26 14:19:08 +02:00
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//! Generalization of a state machine for a consensus engine.
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//! This will define traits for the header, block, and state of a blockchain.
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2019-03-13 11:36:13 +01:00
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use ethereum_types::{U256, Address};
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use block::ExecutedBlock;
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2017-09-26 14:19:08 +02:00
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/// Generalization of types surrounding blockchain-suitable state machines.
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pub trait Machine: for<'a> LocalizedMachine<'a> {
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/// A handle to a blockchain client for this machine.
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type EngineClient: ?Sized;
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/// A description of needed auxiliary data.
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type AuxiliaryRequest;
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2018-05-16 08:58:01 +02:00
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/// Actions taken on ancestry blocks when commiting a new block.
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type AncestryAction;
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2017-09-26 14:19:08 +02:00
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/// Errors which can occur when querying or interacting with the machine.
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type Error;
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2019-01-10 13:11:39 +01:00
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/// Get the balance, in base units, associated with an account.
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/// Extracts data from the live block.
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2019-03-13 11:36:13 +01:00
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fn balance(&self, live: &ExecutedBlock, address: &Address) -> Result<U256, Self::Error>;
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2019-01-10 13:11:39 +01:00
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/// Increment the balance of an account in the state of the live block.
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2019-03-13 11:36:13 +01:00
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fn add_balance(&self, live: &mut ExecutedBlock, address: &Address, amount: &U256) -> Result<(), Self::Error>;
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2017-09-26 14:19:08 +02:00
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}
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/// Machine-related types localized to a specific lifetime.
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// TODO: this is a workaround for a lack of associated type constructors in the language.
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pub trait LocalizedMachine<'a>: Sync + Send {
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/// Definition of auxiliary data associated to a specific block.
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type AuxiliaryData: 'a;
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/// A context providing access to the state in a controlled capacity.
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/// Generally also provides verifiable proofs.
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type StateContext: ?Sized + 'a;
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}
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