// Copyright 2015-2018 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 .
//! Trie lookup via HashDB.
use hashdb::{HashDB, Hasher};
use nibbleslice::NibbleSlice;
use node::Node;
use node_codec::NodeCodec;
use super::{Result, TrieError, Query};
use std::marker::PhantomData;
/// Trie lookup helper object.
pub struct Lookup<'a, H: Hasher + 'a, C: NodeCodec, Q: Query> {
/// database to query from.
pub db: &'a HashDB,
/// Query object to record nodes and transform data.
pub query: Q,
/// Hash to start at
pub hash: H::Out,
pub marker: PhantomData, // TODO: probably not needed when all is said and done? When Query is made generic?
}
impl<'a, H, C, Q> Lookup<'a, H, C, Q>
where
H: Hasher + 'a,
C: NodeCodec + 'a,
Q: Query,
{
/// Look up the given key. If the value is found, it will be passed to the given
/// function to decode or copy.
pub fn look_up(mut self, mut key: NibbleSlice) -> Result