Merge pull request #1452 from ethcore/fatdb

FatDB
This commit is contained in:
Nikolay Volf 2016-07-01 14:29:51 +04:00 committed by GitHub
commit b53442953a
11 changed files with 388 additions and 28 deletions

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@ -104,6 +104,21 @@ pub trait HashDB: AsHashDB {
/// } /// }
/// ``` /// ```
fn remove(&mut self, key: &H256); 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<Vec<u8>> {
unimplemented!();
}
/// Removes auxiliary data from hashdb.
fn remove_aux(&mut self, _hash: &[u8]) {
unimplemented!();
}
} }
/// Upcast trait. /// Upcast trait.

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@ -26,6 +26,13 @@ use kvdb::{Database, DBTransaction, DatabaseConfig};
#[cfg(test)] #[cfg(test)]
use std::env; use std::env;
/// Suffix appended to auxiliary keys to distinguish them from normal keys.
/// Would be nich to use rocksdb columns for this eventually.
const AUX_FLAG: u8 = 255;
/// Database version.
const DB_VERSION : u32 = 0x103;
/// Implementation of the `HashDB` trait for a disk-backed database with a memory overlay /// Implementation of the `HashDB` trait for a disk-backed database with a memory overlay
/// and latent-removal semantics. /// and latent-removal semantics.
/// ///
@ -39,8 +46,6 @@ pub struct ArchiveDB {
latest_era: Option<u64>, latest_era: Option<u64>,
} }
const DB_VERSION : u32 = 0x103;
impl ArchiveDB { impl ArchiveDB {
/// Create a new instance from file /// Create a new instance from file
pub fn new(path: &str, config: DatabaseConfig) -> ArchiveDB { pub fn new(path: &str, config: DatabaseConfig) -> ArchiveDB {
@ -115,12 +120,35 @@ impl HashDB for ArchiveDB {
fn insert(&mut self, value: &[u8]) -> H256 { fn insert(&mut self, value: &[u8]) -> H256 {
self.overlay.insert(value) self.overlay.insert(value)
} }
fn emplace(&mut self, key: H256, value: Bytes) { fn emplace(&mut self, key: H256, value: Bytes) {
self.overlay.emplace(key, value); self.overlay.emplace(key, value);
} }
fn remove(&mut self, key: &H256) { fn remove(&mut self, key: &H256) {
self.overlay.remove(key); self.overlay.remove(key);
} }
fn insert_aux(&mut self, hash: Vec<u8>, value: Vec<u8>) {
self.overlay.insert_aux(hash, value);
}
fn get_aux(&self, hash: &[u8]) -> Option<Vec<u8>> {
if let Some(res) = self.overlay.get_aux(hash) {
return Some(res)
}
let mut db_hash = hash.to_vec();
db_hash.push(AUX_FLAG);
self.backing.get(&db_hash)
.expect("Low-level database error. Some issue with your hard disk?")
.map(|v| v.to_vec())
}
fn remove_aux(&mut self, hash: &[u8]) {
self.overlay.remove_aux(hash);
}
} }
impl JournalDB for ArchiveDB { impl JournalDB for ArchiveDB {
@ -144,6 +172,7 @@ impl JournalDB for ArchiveDB {
let batch = DBTransaction::new(); let batch = DBTransaction::new();
let mut inserts = 0usize; let mut inserts = 0usize;
let mut deletes = 0usize; let mut deletes = 0usize;
for i in self.overlay.drain().into_iter() { for i in self.overlay.drain().into_iter() {
let (key, (value, rc)) = i; let (key, (value, rc)) = i;
if rc > 0 { if rc > 0 {
@ -156,6 +185,12 @@ impl JournalDB for ArchiveDB {
deletes += 1; deletes += 1;
} }
} }
for (mut key, value) in self.overlay.drain_aux().into_iter() {
key.push(AUX_FLAG);
batch.put(&key, &value).expect("Low-level database error. Some issue with your hard disk?");
}
if self.latest_era.map_or(true, |e| now > e) { if self.latest_era.map_or(true, |e| now > e) {
try!(batch.put(&LATEST_ERA_KEY, &encode(&now))); try!(batch.put(&LATEST_ERA_KEY, &encode(&now)));
self.latest_era = Some(now); self.latest_era = Some(now);

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@ -74,6 +74,7 @@ use std::default::Default;
pub struct MemoryDB { pub struct MemoryDB {
data: HashMap<H256, (Bytes, i32)>, data: HashMap<H256, (Bytes, i32)>,
static_null_rlp: (Bytes, i32), static_null_rlp: (Bytes, i32),
aux: HashMap<Bytes, Bytes>,
} }
impl Default for MemoryDB { impl Default for MemoryDB {
@ -88,6 +89,7 @@ impl MemoryDB {
MemoryDB { MemoryDB {
data: HashMap::new(), data: HashMap::new(),
static_null_rlp: (vec![0x80u8; 1], 1), static_null_rlp: (vec![0x80u8; 1], 1),
aux: HashMap::new(),
} }
} }
@ -134,9 +136,12 @@ impl MemoryDB {
/// Return the internal map of hashes to data, clearing the current state. /// Return the internal map of hashes to data, clearing the current state.
pub fn drain(&mut self) -> HashMap<H256, (Bytes, i32)> { pub fn drain(&mut self) -> HashMap<H256, (Bytes, i32)> {
let mut data = HashMap::new(); mem::replace(&mut self.data, HashMap::new())
mem::swap(&mut self.data, &mut data); }
data
/// Return the internal map of auxiliary data, clearing the current state.
pub fn drain_aux(&mut self) -> HashMap<Bytes, Bytes> {
mem::replace(&mut self.aux, HashMap::new())
} }
/// Denote than an existing value has the given key. Used when a key gets removed without /// Denote than an existing value has the given key. Used when a key gets removed without
@ -233,6 +238,18 @@ impl HashDB for MemoryDB {
self.data.insert(key.clone(), (Bytes::new(), -1)); self.data.insert(key.clone(), (Bytes::new(), -1));
} }
} }
fn insert_aux(&mut self, hash: Vec<u8>, value: Vec<u8>) {
self.aux.insert(hash, value);
}
fn get_aux(&self, hash: &[u8]) -> Option<Vec<u8>> {
self.aux.get(hash).cloned()
}
fn remove_aux(&mut self, hash: &[u8]) {
self.aux.remove(hash);
}
} }
#[test] #[test]

112
util/src/trie/fatdb.rs Normal file
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@ -0,0 +1,112 @@
// 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/>.
use hash::H256;
use sha3::Hashable;
use hashdb::HashDB;
use super::{TrieDB, Trie, TrieDBIterator, TrieError};
/// A `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
/// Additionaly it stores inserted hash-key mappings for later retrieval.
///
/// Use it as a `Trie` or `TrieMut` trait object.
pub struct FatDB<'db> {
raw: TrieDB<'db>,
}
impl<'db> FatDB<'db> {
/// Create a new trie with the backing database `db` and empty `root`
/// Initialise to the state entailed by the genesis block.
/// This guarantees the trie is built correctly.
pub fn new(db: &'db HashDB, root: &'db H256) -> Result<Self, TrieError> {
let fatdb = FatDB {
raw: try!(TrieDB::new(db, root))
};
Ok(fatdb)
}
/// Get the backing database.
pub fn db(&self) -> &HashDB {
self.raw.db()
}
/// Iterator over all key / vlaues in the trie.
pub fn iter(&self) -> FatDBIterator {
FatDBIterator::new(&self.raw)
}
}
impl<'db> Trie for FatDB<'db> {
fn iter<'a>(&'a self) -> Box<Iterator<Item = (Vec<u8>, &[u8])> + 'a> {
Box::new(FatDB::iter(self))
}
fn root(&self) -> &H256 {
self.raw.root()
}
fn contains(&self, key: &[u8]) -> bool {
self.raw.contains(&key.sha3())
}
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
self.raw.get(&key.sha3())
}
}
/// Itarator over inserted pairs of key values.
pub struct FatDBIterator<'db> {
trie_iterator: TrieDBIterator<'db>,
trie: &'db TrieDB<'db>,
}
impl<'db> FatDBIterator<'db> {
/// Creates new iterator.
pub fn new(trie: &'db TrieDB) -> Self {
FatDBIterator {
trie_iterator: TrieDBIterator::new(trie),
trie: trie,
}
}
}
impl<'db> Iterator for FatDBIterator<'db> {
type Item = (Vec<u8>, &'db [u8]);
fn next(&mut self) -> Option<Self::Item> {
self.trie_iterator.next()
.map(|(hash, value)| {
(self.trie.db().get_aux(&hash).expect("Missing fatdb hash"), value)
})
}
}
#[test]
fn fatdb_to_trie() {
use memorydb::MemoryDB;
use trie::{FatDBMut, TrieMut};
let mut memdb = MemoryDB::new();
let mut root = H256::default();
{
let mut t = FatDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]);
}
let t = FatDB::new(&memdb, &root).unwrap();
assert_eq!(t.get(&[0x01u8, 0x23]).unwrap(), &[0x01u8, 0x23]);
assert_eq!(t.iter().collect::<Vec<_>>(), vec![(vec![0x01u8, 0x23], &[0x01u8, 0x23] as &[u8])]);
}

94
util/src/trie/fatdbmut.rs Normal file
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@ -0,0 +1,94 @@
// 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/>.
use hash::H256;
use sha3::Hashable;
use hashdb::HashDB;
use super::{TrieDBMut, Trie, TrieMut, TrieError};
/// A mutable `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
/// Additionaly it stores inserted hash-key mappings for later retrieval.
///
/// Use it as a `Trie` or `TrieMut` trait object.
pub struct FatDBMut<'db> {
raw: TrieDBMut<'db>,
}
impl<'db> FatDBMut<'db> {
/// Create a new trie with the backing database `db` and empty `root`
/// Initialise to the state entailed by the genesis block.
/// This guarantees the trie is built correctly.
pub fn new(db: &'db mut HashDB, root: &'db mut H256) -> Self {
FatDBMut { raw: TrieDBMut::new(db, root) }
}
/// Create a new trie with the backing database `db` and `root`.
///
/// Returns an error if root does not exist.
pub fn from_existing(db: &'db mut HashDB, root: &'db mut H256) -> Result<Self, TrieError> {
Ok(FatDBMut { raw: try!(TrieDBMut::from_existing(db, root)) })
}
/// Get the backing database.
pub fn db(&self) -> &HashDB {
self.raw.db()
}
/// Get the backing database.
pub fn db_mut(&mut self) -> &mut HashDB {
self.raw.db_mut()
}
}
impl<'db> TrieMut for FatDBMut<'db> {
fn root(&self) -> &H256 {
self.raw.root()
}
fn contains(&self, key: &[u8]) -> bool {
self.raw.contains(&key.sha3())
}
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
self.raw.get(&key.sha3())
}
fn insert(&mut self, key: &[u8], value: &[u8]) {
let hash = key.sha3();
self.raw.insert(&hash, value);
let db = self.raw.db_mut();
db.insert_aux(hash.to_vec(), key.to_vec());
}
fn remove(&mut self, key: &[u8]) {
self.raw.remove(&key.sha3());
}
}
#[test]
fn fatdb_to_trie() {
use memorydb::MemoryDB;
use super::TrieDB;
let mut memdb = MemoryDB::new();
let mut root = H256::default();
{
let mut t = FatDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]);
}
let t = TrieDB::new(&memdb, &root).unwrap();
assert_eq!(t.get(&(&[0x01u8, 0x23]).sha3()).unwrap(), &[0x01u8, 0x23]);
}

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@ -17,6 +17,8 @@
//! Trie interface and implementation. //! Trie interface and implementation.
use std::fmt; use std::fmt;
use hash::H256;
use hashdb::HashDB;
/// Export the trietraits module. /// Export the trietraits module.
pub mod trietraits; pub mod trietraits;
@ -35,12 +37,18 @@ pub mod sectriedb;
/// Export the sectriedbmut module. /// Export the sectriedbmut module.
pub mod sectriedbmut; pub mod sectriedbmut;
mod fatdb;
mod fatdbmut;
pub use self::trietraits::{Trie, TrieMut}; pub use self::trietraits::{Trie, TrieMut};
pub use self::standardmap::{Alphabet, StandardMap, ValueMode}; pub use self::standardmap::{Alphabet, StandardMap, ValueMode};
pub use self::triedbmut::TrieDBMut; pub use self::triedbmut::TrieDBMut;
pub use self::triedb::TrieDB; pub use self::triedb::{TrieDB, TrieDBIterator};
pub use self::sectriedbmut::SecTrieDBMut; pub use self::sectriedbmut::SecTrieDBMut;
pub use self::sectriedb::SecTrieDB; pub use self::sectriedb::SecTrieDB;
pub use self::fatdb::{FatDB, FatDBIterator};
pub use self::fatdbmut::FatDBMut;
/// Trie Errors /// Trie Errors
#[derive(Debug)] #[derive(Debug)]
@ -53,4 +61,63 @@ impl fmt::Display for TrieError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Trie Error: Invalid state root.") write!(f, "Trie Error: Invalid state root.")
} }
} }
/// Trie types
#[derive(Debug, Clone)]
pub enum TrieSpec {
/// Generic trie.
Generic,
/// Secure trie.
Secure,
/// Secure trie with fat database.
Fat,
}
impl Default for TrieSpec {
fn default() -> TrieSpec {
TrieSpec::Secure
}
}
/// Trie factory.
#[derive(Default, Clone)]
pub struct TrieFactory {
spec: TrieSpec,
}
impl TrieFactory {
/// Creates new factory.
pub fn new(spec: TrieSpec) -> Self {
TrieFactory {
spec: spec,
}
}
/// Create new immutable instance of Trie.
pub fn readonly<'db>(&self, db: &'db HashDB, root: &'db H256) -> Result<Box<Trie + 'db>, TrieError> {
match self.spec {
TrieSpec::Generic => Ok(Box::new(try!(TrieDB::new(db, root)))),
TrieSpec::Secure => Ok(Box::new(try!(SecTrieDB::new(db, root)))),
TrieSpec::Fat => Ok(Box::new(try!(FatDB::new(db, root)))),
}
}
/// Create new mutable instance of Trie.
pub fn create<'db>(&self, db: &'db mut HashDB, root: &'db mut H256) -> Box<TrieMut + 'db> {
match self.spec {
TrieSpec::Generic => Box::new(TrieDBMut::new(db, root)),
TrieSpec::Secure => Box::new(SecTrieDBMut::new(db, root)),
TrieSpec::Fat => Box::new(FatDBMut::new(db, root)),
}
}
/// Create new mutable instance of trie and check for errors.
pub fn from_existing<'db>(&self, db: &'db mut HashDB, root: &'db mut H256) -> Result<Box<TrieMut + 'db>, TrieError> {
match self.spec {
TrieSpec::Generic => Ok(Box::new(try!(TrieDBMut::from_existing(db, root)))),
TrieSpec::Secure => Ok(Box::new(try!(SecTrieDBMut::from_existing(db, root)))),
TrieSpec::Fat => Ok(Box::new(try!(FatDBMut::from_existing(db, root)))),
}
}
}

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@ -14,8 +14,8 @@
// You should have received a copy of the GNU General Public License // You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>. // along with Parity. If not, see <http://www.gnu.org/licenses/>.
use hash::*; use hash::H256;
use sha3::*; use sha3::Hashable;
use hashdb::HashDB; use hashdb::HashDB;
use super::triedb::TrieDB; use super::triedb::TrieDB;
use super::trietraits::Trie; use super::trietraits::Trie;
@ -50,6 +50,10 @@ impl<'db> SecTrieDB<'db> {
} }
impl<'db> Trie for SecTrieDB<'db> { impl<'db> Trie for SecTrieDB<'db> {
fn iter<'a>(&'a self) -> Box<Iterator<Item = (Vec<u8>, &[u8])> + 'a> {
Box::new(TrieDB::iter(&self.raw))
}
fn root(&self) -> &H256 { self.raw.root() } fn root(&self) -> &H256 { self.raw.root() }
fn contains(&self, key: &[u8]) -> bool { fn contains(&self, key: &[u8]) -> bool {
@ -68,7 +72,7 @@ fn trie_to_sectrie() {
use super::trietraits::TrieMut; use super::trietraits::TrieMut;
let mut memdb = MemoryDB::new(); let mut memdb = MemoryDB::new();
let mut root = H256::new(); let mut root = H256::default();
{ {
let mut t = TrieDBMut::new(&mut memdb, &mut root); let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&(&[0x01u8, 0x23]).sha3(), &[0x01u8, 0x23]); t.insert(&(&[0x01u8, 0x23]).sha3(), &[0x01u8, 0x23]);

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@ -14,8 +14,8 @@
// You should have received a copy of the GNU General Public License // You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>. // along with Parity. If not, see <http://www.gnu.org/licenses/>.
use hash::*; use hash::H256;
use sha3::*; use sha3::Hashable;
use hashdb::HashDB; use hashdb::HashDB;
use super::triedbmut::TrieDBMut; use super::triedbmut::TrieDBMut;
use super::trietraits::{Trie, TrieMut}; use super::trietraits::{Trie, TrieMut};
@ -44,13 +44,13 @@ impl<'db> SecTrieDBMut<'db> {
} }
/// Get the backing database. /// Get the backing database.
pub fn db(&'db self) -> &'db HashDB { self.raw.db() } pub fn db(&self) -> &HashDB { self.raw.db() }
/// Get the backing database. /// Get the backing database.
pub fn db_mut(&'db mut self) -> &'db mut HashDB { self.raw.db_mut() } pub fn db_mut(&mut self) -> &mut HashDB { self.raw.db_mut() }
} }
impl<'db> Trie for SecTrieDBMut<'db> { impl<'db> TrieMut for SecTrieDBMut<'db> {
fn root(&self) -> &H256 { self.raw.root() } fn root(&self) -> &H256 { self.raw.root() }
fn contains(&self, key: &[u8]) -> bool { fn contains(&self, key: &[u8]) -> bool {
@ -60,9 +60,7 @@ impl<'db> Trie for SecTrieDBMut<'db> {
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key { fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
self.raw.get(&key.sha3()) self.raw.get(&key.sha3())
} }
}
impl<'db> TrieMut for SecTrieDBMut<'db> {
fn insert(&mut self, key: &[u8], value: &[u8]) { fn insert(&mut self, key: &[u8], value: &[u8]) {
self.raw.insert(&key.sha3(), value); self.raw.insert(&key.sha3(), value);
} }
@ -78,7 +76,7 @@ fn sectrie_to_trie() {
use super::triedb::*; use super::triedb::*;
let mut memdb = MemoryDB::new(); let mut memdb = MemoryDB::new();
let mut root = H256::new(); let mut root = H256::default();
{ {
let mut t = SecTrieDBMut::new(&mut memdb, &mut root); let mut t = SecTrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]); t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]);

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@ -18,7 +18,7 @@ use common::*;
use hashdb::*; use hashdb::*;
use nibbleslice::*; use nibbleslice::*;
use rlp::*; use rlp::*;
use super::trietraits::Trie; use super::trietraits::{Trie};
use super::node::Node; use super::node::Node;
use super::TrieError; use super::TrieError;
@ -257,7 +257,7 @@ pub struct TrieDBIterator<'a> {
impl<'a> TrieDBIterator<'a> { impl<'a> TrieDBIterator<'a> {
/// Create a new iterator. /// Create a new iterator.
fn new(db: &'a TrieDB) -> TrieDBIterator<'a> { pub fn new(db: &'a TrieDB) -> TrieDBIterator<'a> {
let mut r = TrieDBIterator { let mut r = TrieDBIterator {
db: db, db: db,
trail: vec![], trail: vec![],
@ -331,10 +331,16 @@ impl<'a> Iterator for TrieDBIterator<'a> {
impl<'db> TrieDB<'db> { impl<'db> TrieDB<'db> {
/// Get all keys/values stored in the trie. /// Get all keys/values stored in the trie.
pub fn iter(&self) -> TrieDBIterator { TrieDBIterator::new(self) } pub fn iter(&self) -> TrieDBIterator {
TrieDBIterator::new(self)
}
} }
impl<'db> Trie for TrieDB<'db> { impl<'db> Trie for TrieDB<'db> {
fn iter<'a>(&'a self) -> Box<Iterator<Item = (Vec<u8>, &[u8])> + 'a> {
Box::new(TrieDB::iter(self))
}
fn root(&self) -> &H256 { &self.root } fn root(&self) -> &H256 { &self.root }
fn contains(&self, key: &[u8]) -> bool { fn contains(&self, key: &[u8]) -> bool {

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@ -99,12 +99,12 @@ impl<'db> TrieDBMut<'db> {
} }
/// Get the backing database. /// Get the backing database.
pub fn db(&'db self) -> &'db HashDB { pub fn db(&self) -> &HashDB {
self.db self.db
} }
/// Get the backing database. /// Get the backing database.
pub fn db_mut(&'db mut self) -> &'db mut HashDB { pub fn db_mut(&mut self) -> &mut HashDB {
self.db self.db
} }
@ -642,7 +642,7 @@ impl<'db> TrieDBMut<'db> {
} }
} }
impl<'db> Trie for TrieDBMut<'db> { impl<'db> TrieMut for TrieDBMut<'db> {
fn root(&self) -> &H256 { &self.root } fn root(&self) -> &H256 { &self.root }
fn contains(&self, key: &[u8]) -> bool { fn contains(&self, key: &[u8]) -> bool {
@ -652,9 +652,7 @@ impl<'db> Trie for TrieDBMut<'db> {
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key { fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
self.do_lookup(&NibbleSlice::new(key)) self.do_lookup(&NibbleSlice::new(key))
} }
}
impl<'db> TrieMut for TrieDBMut<'db> {
fn insert(&mut self, key: &[u8], value: &[u8]) { fn insert(&mut self, key: &[u8], value: &[u8]) {
match value.is_empty() { match value.is_empty() {
false => self.insert_ns(&NibbleSlice::new(key), value), false => self.insert_ns(&NibbleSlice::new(key), value),

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@ -30,10 +30,25 @@ pub trait Trie {
/// What is the value of the given key in this trie? /// What is the value of the given key in this trie?
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key; fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key;
/// Returns an iterator over elements of trie.
fn iter<'a>(&'a self) -> Box<Iterator<Item = (Vec<u8>, &[u8])> + 'a>;
} }
/// A key-value datastore implemented as a database-backed modified Merkle tree. /// A key-value datastore implemented as a database-backed modified Merkle tree.
pub trait TrieMut: Trie { pub trait TrieMut {
/// Return the root of the trie.
fn root(&self) -> &H256;
/// Is the trie empty?
fn is_empty(&self) -> bool { *self.root() == SHA3_NULL_RLP }
/// Does the trie contain a given key?
fn contains(&self, key: &[u8]) -> bool;
/// What is the value of the given key in this trie?
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key;
/// Insert a `key`/`value` pair into the trie. An `empty` value is equivalent to removing /// Insert a `key`/`value` pair into the trie. An `empty` value is equivalent to removing
/// `key` from the trie. /// `key` from the trie.
fn insert(&mut self, key: &[u8], value: &[u8]); fn insert(&mut self, key: &[u8], value: &[u8]);
@ -42,4 +57,3 @@ pub trait TrieMut: Trie {
/// value. /// value.
fn remove(&mut self, key: &[u8]); fn remove(&mut self, key: &[u8]);
} }