46 lines
1.6 KiB
Rust
46 lines
1.6 KiB
Rust
// Copyright 2015, 2016 Ethcore (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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use hash::H256;
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use rlp::SHA3_NULL_RLP;
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/// A key-value datastore implemented as a database-backed modified Merkle tree.
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pub trait Trie {
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/// Return the root of the trie.
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fn root(&self) -> &H256;
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/// Is the trie empty?
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fn is_empty(&self) -> bool { *self.root() == SHA3_NULL_RLP }
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/// Does the trie contain a given key?
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fn contains(&self, key: &[u8]) -> bool;
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/// What is the value of the given key in this trie?
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fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key;
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}
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/// A key-value datastore implemented as a database-backed modified Merkle tree.
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pub trait TrieMut: Trie {
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/// Insert a `key`/`value` pair into the trie. An `empty` value is equivalent to removing
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/// `key` from the trie.
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fn insert(&mut self, key: &[u8], value: &[u8]);
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/// Remove a `key` from the trie. Equivalent to making it equal to the empty
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/// value.
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fn remove(&mut self, key: &[u8]);
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}
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