86 lines
2.6 KiB
Rust
86 lines
2.6 KiB
Rust
// Copyright 2015-2018 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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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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// Parity is distributed in the hope that it will be useful,
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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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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Trait for fetching chain data.
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use std::sync::Arc;
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use ethcore::encoded;
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use ethcore::engines::{EthEngine, StateDependentProof};
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use ethcore::machine::EthereumMachine;
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use ethcore::header::Header;
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use ethcore::receipt::Receipt;
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use futures::future::IntoFuture;
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use ethereum_types::H256;
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/// Provides full chain data.
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pub trait ChainDataFetcher: Send + Sync + 'static {
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/// Error type when data unavailable.
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type Error: ::std::fmt::Debug;
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/// Future for fetching block body.
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type Body: IntoFuture<Item=encoded::Block, Error=Self::Error>;
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/// Future for fetching block receipts.
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type Receipts: IntoFuture<Item=Vec<Receipt>, Error=Self::Error>;
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/// Future for fetching epoch transition
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type Transition: IntoFuture<Item=Vec<u8>, Error=Self::Error>;
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/// Fetch a block body.
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fn block_body(&self, header: &Header) -> Self::Body;
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/// Fetch block receipts.
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fn block_receipts(&self, header: &Header) -> Self::Receipts;
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/// Fetch epoch transition proof at given header.
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fn epoch_transition(
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&self,
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_hash: H256,
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_engine: Arc<EthEngine>,
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_checker: Arc<StateDependentProof<EthereumMachine>>
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) -> Self::Transition;
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}
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/// Fetcher implementation which cannot fetch anything.
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pub struct Unavailable;
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/// Create a fetcher which has all data unavailable.
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pub fn unavailable() -> Unavailable { Unavailable }
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impl ChainDataFetcher for Unavailable {
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type Error = &'static str;
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type Body = Result<encoded::Block, &'static str>;
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type Receipts = Result<Vec<Receipt>, &'static str>;
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type Transition = Result<Vec<u8>, &'static str>;
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fn block_body(&self, _header: &Header) -> Self::Body {
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Err("fetching block bodies unavailable")
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}
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fn block_receipts(&self, _header: &Header) -> Self::Receipts {
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Err("fetching block receipts unavailable")
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}
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fn epoch_transition(
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&self,
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_hash: H256,
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_engine: Arc<EthEngine>,
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_checker: Arc<StateDependentProof<EthereumMachine>>
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) -> Self::Transition {
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Err("fetching epoch transition proofs unavailable")
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}
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}
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