71 lines
2.5 KiB
Rust
71 lines
2.5 KiB
Rust
// Copyright 2017 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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//! A service transactions contract checker.
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use futures::{future, Future};
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use native_contracts::ServiceTransactionChecker as Contract;
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use ethereum_types::{U256, Address};
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use parking_lot::Mutex;
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use transaction::SignedTransaction;
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use types::ids::BlockId;
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const SERVICE_TRANSACTION_CONTRACT_REGISTRY_NAME: &'static str = "service_transaction_checker";
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/// A contract calling interface.
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pub trait ContractCaller {
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/// Returns address of contract from the registry, given it's name
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fn registry_address(&self, name: &str) -> Option<Address>;
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/// Executes a contract call at given block.
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fn call_contract(&self, BlockId, Address, Vec<u8>) -> Result<Vec<u8>, String>;
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}
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/// Service transactions checker.
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#[derive(Default)]
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pub struct ServiceTransactionChecker {
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contract: Mutex<Option<Contract>>,
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}
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impl ServiceTransactionChecker {
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/// Try to create instance, reading contract address from given chain client.
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pub fn update_from_chain_client(&self, client: &ContractCaller) {
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let mut contract = self.contract.lock();
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if contract.is_none() {
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*contract = client.registry_address(SERVICE_TRANSACTION_CONTRACT_REGISTRY_NAME)
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.and_then(|contract_addr| {
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trace!(target: "txqueue", "Configuring for service transaction checker contract from {}", contract_addr);
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Some(Contract::new(contract_addr))
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})
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}
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}
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/// Checks if service transaction can be appended to the transaction queue.
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pub fn check(&self, client: &ContractCaller, tx: &SignedTransaction) -> Result<bool, String> {
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debug_assert_eq!(tx.gas_price, U256::zero());
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if let Some(ref contract) = *self.contract.lock() {
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contract.certified(
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|addr, data| future::done(client.call_contract(BlockId::Latest, addr, data)),
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tx.sender()
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).wait()
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} else {
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Err("contract is not configured".to_owned())
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}
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}
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}
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