143 lines
4.3 KiB
Rust
143 lines
4.3 KiB
Rust
// Copyright 2015, 2016 Ethcore (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/>.
|
|
|
|
//! Database of byte-slices keyed to their Keccak hash.
|
|
use hash::*;
|
|
use std::collections::HashMap;
|
|
use elastic_array::ElasticArray128;
|
|
|
|
/// `HashDB` value type.
|
|
pub type DBValue = ElasticArray128<u8>;
|
|
|
|
/// Trait modelling datastore keyed by a 32-byte Keccak hash.
|
|
pub trait HashDB: AsHashDB + Send + Sync {
|
|
/// Get the keys in the database together with number of underlying references.
|
|
fn keys(&self) -> HashMap<H256, i32>;
|
|
|
|
/// Look up a given hash into the bytes that hash to it, returning None if the
|
|
/// hash is not known.
|
|
///
|
|
/// # Examples
|
|
/// ```rust
|
|
/// extern crate ethcore_util;
|
|
/// use ethcore_util::hashdb::*;
|
|
/// use ethcore_util::memorydb::*;
|
|
/// fn main() {
|
|
/// let mut m = MemoryDB::new();
|
|
/// let hello_bytes = "Hello world!".as_bytes();
|
|
/// let hash = m.insert(hello_bytes);
|
|
/// assert_eq!(m.get(&hash).unwrap(), hello_bytes);
|
|
/// }
|
|
/// ```
|
|
fn get(&self, key: &H256) -> Option<DBValue>;
|
|
|
|
/// Check for the existance of a hash-key.
|
|
///
|
|
/// # Examples
|
|
/// ```rust
|
|
/// extern crate ethcore_util;
|
|
/// use ethcore_util::hashdb::*;
|
|
/// use ethcore_util::memorydb::*;
|
|
/// use ethcore_util::sha3::*;
|
|
/// fn main() {
|
|
/// let mut m = MemoryDB::new();
|
|
/// let hello_bytes = "Hello world!".as_bytes();
|
|
/// assert!(!m.contains(&hello_bytes.sha3()));
|
|
/// let key = m.insert(hello_bytes);
|
|
/// assert!(m.contains(&key));
|
|
/// m.remove(&key);
|
|
/// assert!(!m.contains(&key));
|
|
/// }
|
|
/// ```
|
|
fn contains(&self, key: &H256) -> bool;
|
|
|
|
/// Insert a datum item into the DB and return the datum's hash for a later lookup. Insertions
|
|
/// are counted and the equivalent number of `remove()`s must be performed before the data
|
|
/// is considered dead.
|
|
///
|
|
/// # Examples
|
|
/// ```rust
|
|
/// extern crate ethcore_util;
|
|
/// use ethcore_util::hashdb::*;
|
|
/// use ethcore_util::memorydb::*;
|
|
/// use ethcore_util::hash::*;
|
|
/// fn main() {
|
|
/// let mut m = MemoryDB::new();
|
|
/// let key = m.insert("Hello world!".as_bytes());
|
|
/// assert!(m.contains(&key));
|
|
/// }
|
|
/// ```
|
|
fn insert(&mut self, value: &[u8]) -> H256;
|
|
|
|
/// Like `insert()` , except you provide the key and the data is all moved.
|
|
fn emplace(&mut self, key: H256, value: DBValue);
|
|
|
|
/// Remove a datum previously inserted. Insertions can be "owed" such that the same number of `insert()`s may
|
|
/// happen without the data being eventually being inserted into the DB.
|
|
///
|
|
/// # Examples
|
|
/// ```rust
|
|
/// extern crate ethcore_util;
|
|
/// use ethcore_util::hashdb::*;
|
|
/// use ethcore_util::memorydb::*;
|
|
/// use ethcore_util::sha3::*;
|
|
/// fn main() {
|
|
/// let mut m = MemoryDB::new();
|
|
/// let d = "Hello world!".as_bytes();
|
|
/// let key = &d.sha3();
|
|
/// m.remove(key); // OK - we now owe an insertion.
|
|
/// assert!(!m.contains(key));
|
|
/// m.insert(d); // OK - now it's "empty" again.
|
|
/// assert!(!m.contains(key));
|
|
/// m.insert(d); // OK - now we've
|
|
/// assert_eq!(m.get(key).unwrap(), d);
|
|
/// }
|
|
/// ```
|
|
fn remove(&mut self, key: &H256);
|
|
|
|
/// Insert auxiliary data into hashdb.
|
|
fn insert_aux(&mut self, _hash: Vec<u8>, _value: Vec<u8>) {
|
|
unimplemented!();
|
|
}
|
|
|
|
/// Get auxiliary data from hashdb.
|
|
fn get_aux(&self, _hash: &[u8]) -> Option<DBValue> {
|
|
unimplemented!();
|
|
}
|
|
|
|
/// Removes auxiliary data from hashdb.
|
|
fn remove_aux(&mut self, _hash: &[u8]) {
|
|
unimplemented!();
|
|
}
|
|
}
|
|
|
|
/// Upcast trait.
|
|
pub trait AsHashDB {
|
|
/// Perform upcast to HashDB for anything that derives from HashDB.
|
|
fn as_hashdb(&self) -> &HashDB;
|
|
/// Perform mutable upcast to HashDB for anything that derives from HashDB.
|
|
fn as_hashdb_mut(&mut self) -> &mut HashDB;
|
|
}
|
|
|
|
impl<T: HashDB> AsHashDB for T {
|
|
fn as_hashdb(&self) -> &HashDB {
|
|
self
|
|
}
|
|
fn as_hashdb_mut(&mut self) -> &mut HashDB {
|
|
self
|
|
}
|
|
}
|