openethereum/registrar/src/registrar.rs

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// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.
// Parity 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.
// Parity 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 Parity. If not, see <http://www.gnu.org/licenses/>.
use futures::{Future, future, IntoFuture};
use ethabi::{Address, Bytes};
use std::sync::Arc;
use keccak_hash::keccak;
use_contract!(registry, "Registry", "res/registrar.json");
// Maps a domain name to an Ethereum address
const DNS_A_RECORD: &'static str = "A";
pub type Asynchronous = Box<Future<Item=Bytes, Error=String> + Send>;
pub type Synchronous = Result<Bytes, String>;
/// Registrar is dedicated interface to access the registrar contract
/// which in turn generates an address when a client requests one
pub struct Registrar {
registrar: registry::Registry,
client: Arc<RegistrarClient<Call=Asynchronous>>,
}
impl Registrar {
/// Registrar constructor
pub fn new(client: Arc<RegistrarClient<Call=Asynchronous>>) -> Self {
Self {
registrar: registry::Registry::default(),
client: client,
}
}
/// Generate an address for the given key
pub fn get_address<'a>(&self, key: &'a str) -> Box<Future<Item = Address, Error = String> + Send> {
// Address of the registrar itself
let registrar_address = match self.client.registrar_address() {
Ok(a) => a,
Err(e) => return Box::new(future::err(e)),
};
let address_fetcher = self.registrar.functions().get_address();
let id = address_fetcher.input(keccak(key), DNS_A_RECORD);
let future = self.client.call_contract(registrar_address, id).and_then(move |address| {
address_fetcher.output(&address)
}
.map_err(|e| e.to_string()));
Box::new(future)
}
}
/// Registrar contract interface
/// Should execute transaction using current blockchain state.
pub trait RegistrarClient: Send + Sync {
/// Specifies synchronous or asynchronous communication
type Call: IntoFuture<Item=Bytes, Error=String>;
/// Get registrar address
fn registrar_address(&self) -> Result<Address, String>;
/// Call Contract
fn call_contract(&self, address: Address, data: Bytes) -> Self::Call;
}