375 lines
11 KiB
Rust
375 lines
11 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/>.
|
|
|
|
use common::*;
|
|
use hashdb::*;
|
|
use nibbleslice::*;
|
|
use rlp::*;
|
|
use super::trietraits::*;
|
|
use super::node::*;
|
|
|
|
/// A `Trie` implementation using a generic `HashDB` backing database.
|
|
///
|
|
/// Use it as a `Trie` trait object. You can use `db()` to get the backing database object, `keys`
|
|
/// to get the keys belonging to the trie in the backing database, and `db_items_remaining()` to get
|
|
/// which items in the backing database do not belong to this trie. If this is the only trie in the
|
|
/// backing database, then `db_items_remaining()` should be empty.
|
|
///
|
|
/// # Example
|
|
/// ```
|
|
/// extern crate ethcore_util as util;
|
|
/// use util::trie::*;
|
|
/// use util::hashdb::*;
|
|
/// use util::memorydb::*;
|
|
/// use util::hash::*;
|
|
/// use util::rlp::*;
|
|
///
|
|
/// fn main() {
|
|
/// let mut memdb = MemoryDB::new();
|
|
/// let mut root = H256::new();
|
|
/// TrieDBMut::new(&mut memdb, &mut root).insert(b"foo", b"bar");
|
|
/// let t = TrieDB::new(&memdb, &root);
|
|
/// assert!(t.contains(b"foo"));
|
|
/// assert_eq!(t.get(b"foo").unwrap(), b"bar");
|
|
/// assert!(t.db_items_remaining().is_empty());
|
|
/// }
|
|
/// ```
|
|
pub struct TrieDB<'db> {
|
|
db: &'db HashDB,
|
|
root: &'db H256,
|
|
/// The number of hashes performed so far in operations on this trie.
|
|
pub hash_count: usize,
|
|
}
|
|
|
|
#[cfg_attr(all(nightly, feature="dev"), allow(wrong_self_convention))]
|
|
impl<'db> TrieDB<'db> {
|
|
/// Create a new trie with the backing database `db` and `root`
|
|
/// Panics, if `root` does not exist
|
|
pub fn new(db: &'db HashDB, root: &'db H256) -> Self {
|
|
if !db.exists(root) {
|
|
flushln!("TrieDB::new({}): Trie root not found!", root);
|
|
panic!("Trie root not found!");
|
|
}
|
|
TrieDB {
|
|
db: db,
|
|
root: root,
|
|
hash_count: 0
|
|
}
|
|
}
|
|
|
|
/// Get the backing database.
|
|
pub fn db(&'db self) -> &'db HashDB {
|
|
self.db
|
|
}
|
|
|
|
/// Determine all the keys in the backing database that belong to the trie.
|
|
pub fn keys(&self) -> Vec<H256> {
|
|
let mut ret: Vec<H256> = Vec::new();
|
|
ret.push(self.root.clone());
|
|
self.accumulate_keys(self.root_node(), &mut ret);
|
|
ret
|
|
}
|
|
|
|
/// Convert a vector of hashes to a hashmap of hash to occurances.
|
|
pub fn to_map(hashes: Vec<H256>) -> HashMap<H256, u32> {
|
|
let mut r: HashMap<H256, u32> = HashMap::new();
|
|
for h in hashes.into_iter() {
|
|
let c = *r.get(&h).unwrap_or(&0);
|
|
r.insert(h, c + 1);
|
|
}
|
|
r
|
|
}
|
|
|
|
/// Determine occurances of items in the backing database which are not related to this
|
|
/// trie.
|
|
pub fn db_items_remaining(&self) -> HashMap<H256, i32> {
|
|
let mut ret = self.db.keys();
|
|
for (k, v) in Self::to_map(self.keys()).into_iter() {
|
|
let keycount = *ret.get(&k).unwrap_or(&0);
|
|
match keycount <= v as i32 {
|
|
true => ret.remove(&k),
|
|
_ => ret.insert(k, keycount - v as i32),
|
|
};
|
|
}
|
|
ret
|
|
}
|
|
|
|
/// Recursion helper for `keys`.
|
|
fn accumulate_keys(&self, node: Node, acc: &mut Vec<H256>) {
|
|
let mut handle_payload = |payload| {
|
|
let p = Rlp::new(payload);
|
|
if p.is_data() && p.size() == 32 {
|
|
acc.push(p.as_val());
|
|
}
|
|
|
|
self.accumulate_keys(self.get_node(payload), acc);
|
|
};
|
|
|
|
match node {
|
|
Node::Extension(_, payload) => handle_payload(payload),
|
|
Node::Branch(payloads, _) => for payload in &payloads { handle_payload(payload) },
|
|
_ => {},
|
|
}
|
|
}
|
|
|
|
/// Get the root node's RLP.
|
|
fn root_node(&self) -> Node {
|
|
Node::decoded(self.root_data())
|
|
}
|
|
|
|
/// Get the data of the root node.
|
|
fn root_data(&self) -> &[u8] {
|
|
self.db.lookup(&self.root).expect("Trie root not found!")
|
|
}
|
|
|
|
/// Get the root node as a `Node`.
|
|
fn get_node<'a>(&'a self, node: &'a [u8]) -> Node {
|
|
Node::decoded(self.get_raw_or_lookup(node))
|
|
}
|
|
|
|
/// Indentation helper for `formal_all`.
|
|
fn fmt_indent(&self, f: &mut fmt::Formatter, size: usize) -> fmt::Result {
|
|
for _ in 0..size {
|
|
try!(write!(f, " "));
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
/// Recursion helper for implementation of formatting trait.
|
|
fn fmt_all(&self, node: Node, f: &mut fmt::Formatter, deepness: usize) -> fmt::Result {
|
|
match node {
|
|
Node::Leaf(slice, value) => try!(writeln!(f, "'{:?}: {:?}.", slice, value.pretty())),
|
|
Node::Extension(ref slice, ref item) => {
|
|
try!(write!(f, "'{:?} ", slice));
|
|
try!(self.fmt_all(self.get_node(item), f, deepness));
|
|
},
|
|
Node::Branch(ref nodes, ref value) => {
|
|
try!(writeln!(f, ""));
|
|
if let Some(v) = *value {
|
|
try!(self.fmt_indent(f, deepness + 1));
|
|
try!(writeln!(f, "=: {:?}", v.pretty()))
|
|
}
|
|
for i in 0..16 {
|
|
match self.get_node(nodes[i]) {
|
|
Node::Empty => {},
|
|
n => {
|
|
try!(self.fmt_indent(f, deepness + 1));
|
|
try!(write!(f, "'{:x} ", i));
|
|
try!(self.fmt_all(n, f, deepness + 1));
|
|
}
|
|
}
|
|
}
|
|
},
|
|
// empty
|
|
Node::Empty => {
|
|
try!(writeln!(f, "<empty>"));
|
|
}
|
|
};
|
|
Ok(())
|
|
}
|
|
|
|
/// Return optional data for a key given as a `NibbleSlice`. Returns `None` if no data exists.
|
|
fn do_lookup<'a, 'key>(&'a self, key: &NibbleSlice<'key>) -> Option<&'a [u8]> where 'a: 'key {
|
|
let root_rlp = self.db.lookup(&self.root).expect("Trie root not found!");
|
|
self.get_from_node(&root_rlp, key)
|
|
}
|
|
|
|
/// Recursible function to retrieve the value given a `node` and a partial `key`. `None` if no
|
|
/// value exists for the key.
|
|
///
|
|
/// Note: Not a public API; use Trie trait functions.
|
|
fn get_from_node<'a, 'key>(&'a self, node: &'a [u8], key: &NibbleSlice<'key>) -> Option<&'a [u8]> where 'a: 'key {
|
|
match Node::decoded(node) {
|
|
Node::Leaf(ref slice, ref value) if key == slice => Some(value),
|
|
Node::Extension(ref slice, ref item) if key.starts_with(slice) => {
|
|
self.get_from_node(self.get_raw_or_lookup(item), &key.mid(slice.len()))
|
|
},
|
|
Node::Branch(ref nodes, value) => match key.is_empty() {
|
|
true => value,
|
|
false => self.get_from_node(self.get_raw_or_lookup(nodes[key.at(0) as usize]), &key.mid(1))
|
|
},
|
|
_ => None
|
|
}
|
|
}
|
|
|
|
/// Given some node-describing data `node`, return the actual node RLP.
|
|
/// This could be a simple identity operation in the case that the node is sufficiently small, but
|
|
/// may require a database lookup.
|
|
fn get_raw_or_lookup<'a>(&'a self, node: &'a [u8]) -> &'a [u8] {
|
|
// check if its sha3 + len
|
|
let r = Rlp::new(node);
|
|
match r.is_data() && r.size() == 32 {
|
|
true => self.db.lookup(&r.as_val::<H256>()).unwrap_or_else(|| panic!("Not found! {:?}", r.as_val::<H256>())),
|
|
false => node
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Eq, PartialEq)]
|
|
enum Status {
|
|
Entering,
|
|
At,
|
|
AtChild(usize),
|
|
Exiting,
|
|
}
|
|
|
|
#[derive(Clone, Eq, PartialEq)]
|
|
struct Crumb<'a> {
|
|
node: Node<'a>,
|
|
// key: &'a[u8],
|
|
status: Status,
|
|
}
|
|
|
|
impl<'a> Crumb<'a> {
|
|
/// Move on to next status in the node's sequence.
|
|
fn increment(&mut self) {
|
|
self.status = match (&self.status, &self.node) {
|
|
(_, &Node::Empty) => Status::Exiting,
|
|
(&Status::Entering, _) => Status::At,
|
|
(&Status::At, &Node::Branch(_, _)) => Status::AtChild(0),
|
|
(&Status::AtChild(x), &Node::Branch(_, _)) if x < 15 => Status::AtChild(x + 1),
|
|
_ => Status::Exiting,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Iterator for going through all values in the trie.
|
|
#[derive(Clone)]
|
|
pub struct TrieDBIterator<'a> {
|
|
db: &'a TrieDB<'a>,
|
|
trail: Vec<Crumb<'a>>,
|
|
key_nibbles: Bytes,
|
|
}
|
|
|
|
impl<'a> TrieDBIterator<'a> {
|
|
/// Create a new iterator.
|
|
fn new(db: &'a TrieDB) -> TrieDBIterator<'a> {
|
|
let mut r = TrieDBIterator {
|
|
db: db,
|
|
trail: vec![],
|
|
key_nibbles: Vec::new(),
|
|
};
|
|
r.descend(db.root_data());
|
|
r
|
|
}
|
|
|
|
/// Descend into a payload.
|
|
fn descend(&mut self, d: &'a [u8]) {
|
|
self.trail.push(Crumb {
|
|
status: Status::Entering,
|
|
node: self.db.get_node(d)
|
|
});
|
|
match self.trail.last().unwrap().node {
|
|
Node::Leaf(n, _) | Node::Extension(n, _) => { self.key_nibbles.extend(n.iter()); },
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
/// Descend into a payload and get the next item.
|
|
fn descend_next(&mut self, d: &'a [u8]) -> Option<(Bytes, &'a [u8])> { self.descend(d); self.next() }
|
|
|
|
/// The present key.
|
|
fn key(&self) -> Bytes {
|
|
// collapse the key_nibbles down to bytes.
|
|
self.key_nibbles.iter().step(2).zip(self.key_nibbles.iter().skip(1).step(2)).map(|(h, l)| h * 16 + l).collect()
|
|
}
|
|
}
|
|
|
|
impl<'a> Iterator for TrieDBIterator<'a> {
|
|
type Item = (Bytes, &'a [u8]);
|
|
|
|
fn next(&mut self) -> Option<Self::Item> {
|
|
let b = match self.trail.last_mut() {
|
|
Some(mut b) => { b.increment(); b.clone() },
|
|
None => return None
|
|
};
|
|
match (b.status, b.node) {
|
|
(Status::Exiting, n) => {
|
|
match n {
|
|
Node::Leaf(n, _) | Node::Extension(n, _) => {
|
|
let l = self.key_nibbles.len();
|
|
self.key_nibbles.truncate(l - n.len());
|
|
},
|
|
Node::Branch(_, _) => { self.key_nibbles.pop(); },
|
|
_ => {}
|
|
}
|
|
self.trail.pop();
|
|
self.next()
|
|
},
|
|
(Status::At, Node::Leaf(_, v)) | (Status::At, Node::Branch(_, Some(v))) => Some((self.key(), v)),
|
|
(Status::At, Node::Extension(_, d)) => self.descend_next(d),
|
|
(Status::At, Node::Branch(_, _)) => self.next(),
|
|
(Status::AtChild(i), Node::Branch(children, _)) if children[i].len() > 0 => {
|
|
match i {
|
|
0 => self.key_nibbles.push(0),
|
|
i => *self.key_nibbles.last_mut().unwrap() = i as u8,
|
|
}
|
|
self.descend_next(children[i])
|
|
},
|
|
(Status::AtChild(i), Node::Branch(_, _)) => {
|
|
if i == 0 { self.key_nibbles.push(0); }
|
|
self.next()
|
|
},
|
|
_ => panic!() // Should never see Entering or AtChild without a Branch here.
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'db> TrieDB<'db> {
|
|
/// Get all keys/values stored in the trie.
|
|
pub fn iter(&self) -> TrieDBIterator { TrieDBIterator::new(self) }
|
|
}
|
|
|
|
impl<'db> Trie for TrieDB<'db> {
|
|
fn root(&self) -> &H256 { &self.root }
|
|
|
|
fn contains(&self, key: &[u8]) -> bool {
|
|
self.get(key).is_some()
|
|
}
|
|
|
|
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
|
|
self.do_lookup(&NibbleSlice::new(key))
|
|
}
|
|
}
|
|
|
|
impl<'db> fmt::Debug for TrieDB<'db> {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
try!(writeln!(f, "c={:?} [", self.hash_count));
|
|
let root_rlp = self.db.lookup(&self.root).expect("Trie root not found!");
|
|
try!(self.fmt_all(Node::decoded(root_rlp), f, 0));
|
|
writeln!(f, "]")
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn iterator() {
|
|
use memorydb::*;
|
|
use super::triedbmut::*;
|
|
|
|
let d = vec![ &b"A"[..], &b"AA"[..], &b"AB"[..], &b"B"[..] ];
|
|
|
|
let mut memdb = MemoryDB::new();
|
|
let mut root = H256::new();
|
|
{
|
|
let mut t = TrieDBMut::new(&mut memdb, &mut root);
|
|
for x in &d {
|
|
t.insert(&x, &x);
|
|
}
|
|
}
|
|
assert_eq!(d.iter().map(|i|i.to_vec()).collect::<Vec<_>>(), TrieDB::new(&memdb, &root).iter().map(|x|x.0).collect::<Vec<_>>());
|
|
assert_eq!(d, TrieDB::new(&memdb, &root).iter().map(|x|x.1).collect::<Vec<_>>());
|
|
}
|