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parity-common/patricia_trie/src/triedbmut.rs

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// 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 <http://www.gnu.org/licenses/>.
//! In-memory trie representation.
use super::{Result, TrieError, TrieMut};
use super::lookup::Lookup;
use super::node::Node as EncodedNode;
use node_codec::NodeCodec;
use super::{DBValue, node::NodeKey};
use bytes::ToPretty;
use hashdb::{HashDB, Hasher};
use nibbleslice::NibbleSlice;
use std::collections::{HashSet, VecDeque};
use std::marker::PhantomData;
use std::mem;
use std::ops::Index;
use std::{fmt::Debug, hash::Hash};
// For lookups into the Node storage buffer.
// This is deliberately non-copyable.
#[derive(Debug)]
struct StorageHandle(usize);
// Handles to nodes in the trie.
#[derive(Debug)]
enum NodeHandle<H> {
/// Loaded into memory.
InMemory(StorageHandle),
/// Either a hash or an inline node
Hash(H),
}
impl<H> From<StorageHandle> for NodeHandle<H> {
fn from(handle: StorageHandle) -> Self {
NodeHandle::InMemory(handle)
}
}
fn empty_children<H>() -> Box<[Option<NodeHandle<H>>; 16]> {
Box::new([
None, None, None, None, None, None, None, None,
None, None, None, None, None, None, None, None,
])
}
/// Node types in the Trie.
#[derive(Debug)]
enum Node<H> {
/// Empty node.
Empty,
/// A leaf node contains the end of a key and a value.
/// This key is encoded from a `NibbleSlice`, meaning it contains
/// a flag indicating it is a leaf.
Leaf(NodeKey, DBValue),
/// An extension contains a shared portion of a key and a child node.
/// The shared portion is encoded from a `NibbleSlice` meaning it contains
/// a flag indicating it is an extension.
/// The child node is always a branch.
Extension(NodeKey, NodeHandle<H>),
/// A branch has up to 16 children and an optional value.
Branch(Box<[Option<NodeHandle<H>>; 16]>, Option<DBValue>)
}
impl<O> Node<O>
where
O: AsRef<[u8]> + AsMut<[u8]> + Default + Debug + PartialEq + Eq + Hash + Send + Sync + Clone + Copy
{
// load an inline node into memory or get the hash to do the lookup later.
fn inline_or_hash<C, H>(
node: &[u8],
db: &HashDB<H, DBValue>,
storage: &mut NodeStorage<H::Out>
) -> NodeHandle<H::Out>
where
C: NodeCodec<H>,
H: Hasher<Out = O>,
{
C::try_decode_hash(&node)
.map(NodeHandle::Hash)
.unwrap_or_else(|| {
let child = Node::from_encoded::<C, H>(node, db, storage);
NodeHandle::InMemory(storage.alloc(Stored::New(child)))
})
}
// decode a node from encoded bytes without getting its children.
fn from_encoded<C, H>(data: &[u8], db: &HashDB<H, DBValue>, storage: &mut NodeStorage<H::Out>) -> Self
where C: NodeCodec<H>,
H: Hasher<Out = O>,
{
match C::decode(data).expect("encoded bytes read from db; qed") {
EncodedNode::Empty => Node::Empty,
EncodedNode::Leaf(k, v) => Node::Leaf(k.encoded(true), DBValue::from_slice(&v)),
EncodedNode::Extension(key, cb) => {
Node::Extension(
key.encoded(false),
Self::inline_or_hash::<C, H>(cb, db, storage))
}
EncodedNode::Branch(ref encoded_children, val) => {
let mut child = |i:usize| {
let raw = encoded_children[i];
if !C::is_empty_node(raw) {
Some(Self::inline_or_hash::<C, H>(raw, db, storage))
} else {
None
}
};
let children = Box::new([
child(0), child(1), child(2), child(3),
child(4), child(5), child(6), child(7),
child(8), child(9), child(10), child(11),
child(12), child(13), child(14), child(15),
]);
Node::Branch(children, val.map(DBValue::from_slice))
}
}
}
// TODO: parallelize
fn into_encoded<F, C, H>(self, mut child_cb: F) -> Vec<u8>
where
C: NodeCodec<H>,
F: FnMut(NodeHandle<H::Out>) -> ChildReference<H::Out>,
H: Hasher<Out = O>,
{
match self {
Node::Empty => C::empty_node(),
Node::Leaf(partial, value) => C::leaf_node(&partial, &value),
Node::Extension(partial, child) => C::ext_node(&partial, child_cb(child)),
Node::Branch(mut children, value) => {
C::branch_node(
// map the `NodeHandle`s from the Branch to `ChildReferences`
children.iter_mut()
.map(Option::take)
.map(|maybe_child|
maybe_child.map(|child| child_cb(child))
),
value
)
}
}
}
}
// post-inspect action.
enum Action<H> {
// Replace a node with a new one.
Replace(Node<H>),
// Restore the original node. This trusts that the node is actually the original.
Restore(Node<H>),
// if it is a new node, just clears the storage.
Delete,
}
// post-insert action. Same as action without delete
enum InsertAction<H> {
// Replace a node with a new one.
Replace(Node<H>),
// Restore the original node.
Restore(Node<H>),
}
impl<H> InsertAction<H> {
fn into_action(self) -> Action<H> {
match self {
InsertAction::Replace(n) => Action::Replace(n),
InsertAction::Restore(n) => Action::Restore(n),
}
}
// unwrap the node, disregarding replace or restore state.
fn unwrap_node(self) -> Node<H> {
match self {
InsertAction::Replace(n) | InsertAction::Restore(n) => n,
}
}
}
// What kind of node is stored here.
enum Stored<H> {
// A new node.
New(Node<H>),
// A cached node, loaded from the DB.
Cached(Node<H>, H),
}
/// Used to build a collection of child nodes from a collection of `NodeHandle`s
pub enum ChildReference<HO> { // `HO` is e.g. `H256`, i.e. the output of a `Hasher`
Hash(HO),
Inline(HO, usize), // usize is the length of the node data we store in the `H::Out`
}
/// Compact and cache-friendly storage for Trie nodes.
struct NodeStorage<H> {
nodes: Vec<Stored<H>>,
free_indices: VecDeque<usize>,
}
impl<H> NodeStorage<H> {
/// Create a new storage.
fn empty() -> Self {
NodeStorage {
nodes: Vec::new(),
free_indices: VecDeque::new(),
}
}
/// Allocate a new node in the storage.
fn alloc(&mut self, stored: Stored<H>) -> StorageHandle {
if let Some(idx) = self.free_indices.pop_front() {
self.nodes[idx] = stored;
StorageHandle(idx)
} else {
self.nodes.push(stored);
StorageHandle(self.nodes.len() - 1)
}
}
/// Remove a node from the storage, consuming the handle and returning the node.
fn destroy(&mut self, handle: StorageHandle) -> Stored<H> {
let idx = handle.0;
self.free_indices.push_back(idx);
mem::replace(&mut self.nodes[idx], Stored::New(Node::Empty))
}
}
impl<'a, H> Index<&'a StorageHandle> for NodeStorage<H> {
type Output = Node<H>;
fn index(&self, handle: &'a StorageHandle) -> &Node<H> {
match self.nodes[handle.0] {
Stored::New(ref node) => node,
Stored::Cached(ref node, _) => node,
}
}
}
/// A `Trie` implementation using a generic `HashDB` backing database.
///
/// Use it as a `TrieMut` trait object. You can use `db()` to get the backing database object.
/// Note that changes are not committed to the database until `commit` is called.
/// Querying the root or dropping the trie will commit automatically.
///
/// # Example
/// ```
/// extern crate patricia_trie as trie;
/// extern crate patricia_trie_ethereum as ethtrie;
/// extern crate hashdb;
/// extern crate keccak_hash;
/// extern crate keccak_hasher;
/// extern crate memorydb;
/// extern crate ethereum_types;
///
/// use keccak_hash::KECCAK_NULL_RLP;
/// use ethtrie::{TrieDBMut, trie::TrieMut};
/// use trie::DBValue;
/// use keccak_hasher::KeccakHasher;
/// use memorydb::*;
/// use ethereum_types::H256;
///
/// fn main() {
/// let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
/// let mut root = H256::new();
/// let mut t = TrieDBMut::new(&mut memdb, &mut root);
/// assert!(t.is_empty());
/// assert_eq!(*t.root(), KECCAK_NULL_RLP);
/// t.insert(b"foo", b"bar").unwrap();
/// assert!(t.contains(b"foo").unwrap());
/// assert_eq!(t.get(b"foo").unwrap().unwrap(), DBValue::from_slice(b"bar"));
/// t.remove(b"foo").unwrap();
/// assert!(!t.contains(b"foo").unwrap());
/// }
/// ```
pub struct TrieDBMut<'a, H, C>
where
H: Hasher + 'a,
C: NodeCodec<H>
{
storage: NodeStorage<H::Out>,
db: &'a mut HashDB<H, DBValue>,
root: &'a mut H::Out,
root_handle: NodeHandle<H::Out>,
death_row: HashSet<H::Out>,
/// The number of hash operations this trie has performed.
/// Note that none are performed until changes are committed.
hash_count: usize,
marker: PhantomData<C>, // TODO: rpheimer: "we could have the NodeCodec trait take &self to its methods and then we don't need PhantomData. we can just store an instance of C: NodeCodec in the trie struct. If it's a ZST it won't have any additional overhead anyway"
}
impl<'a, H, C> TrieDBMut<'a, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
/// Create a new trie with backing database `db` and empty `root`.
pub fn new(db: &'a mut HashDB<H, DBValue>, root: &'a mut H::Out) -> Self {
*root = C::HASHED_NULL_NODE;
let root_handle = NodeHandle::Hash(C::HASHED_NULL_NODE);
TrieDBMut {
storage: NodeStorage::empty(),
db: db,
root: root,
root_handle: root_handle,
death_row: HashSet::new(),
hash_count: 0,
marker: PhantomData,
}
}
/// Create a new trie with the backing database `db` and `root.
/// Returns an error if `root` does not exist.
pub fn from_existing(db: &'a mut HashDB<H, DBValue>, root: &'a mut H::Out) -> Result<Self, H::Out, C::Error> {
if !db.contains(root) {
return Err(Box::new(TrieError::InvalidStateRoot(*root)));
}
let root_handle = NodeHandle::Hash(*root);
Ok(TrieDBMut {
storage: NodeStorage::empty(),
db: db,
root: root,
root_handle: root_handle,
death_row: HashSet::new(),
hash_count: 0,
marker: PhantomData,
})
}
/// Get the backing database.
pub fn db(&self) -> &HashDB<H, DBValue> {
self.db
}
/// Get the backing database mutably.
pub fn db_mut(&mut self) -> &mut HashDB<H, DBValue> {
self.db
}
// cache a node by hash
fn cache(&mut self, hash: H::Out) -> Result<StorageHandle, H::Out, C::Error> {
let node_encoded = self.db.get(&hash).ok_or_else(|| Box::new(TrieError::IncompleteDatabase(hash)))?;
let node = Node::from_encoded::<C, H>(
&node_encoded,
&*self.db,
&mut self.storage
);
Ok(self.storage.alloc(Stored::Cached(node, hash)))
}
// inspect a node, choosing either to replace, restore, or delete it.
// if restored or replaced, returns the new node along with a flag of whether it was changed.
fn inspect<F>(&mut self, stored: Stored<H::Out>, inspector: F) -> Result<Option<(Stored<H::Out>, bool)>, H::Out, C::Error>
where F: FnOnce(&mut Self, Node<H::Out>) -> Result<Action<H::Out>, H::Out, C::Error> {
Ok(match stored {
Stored::New(node) => match inspector(self, node)? {
Action::Restore(node) => Some((Stored::New(node), false)),
Action::Replace(node) => Some((Stored::New(node), true)),
Action::Delete => None,
},
Stored::Cached(node, hash) => match inspector(self, node)? {
Action::Restore(node) => Some((Stored::Cached(node, hash), false)),
Action::Replace(node) => {
self.death_row.insert(hash);
Some((Stored::New(node), true))
}
Action::Delete => {
self.death_row.insert(hash);
None
}
},
})
}
// walk the trie, attempting to find the key's node.
fn lookup<'x, 'key>(&'x self, mut partial: NibbleSlice<'key>, handle: &NodeHandle<H::Out>) -> Result<Option<DBValue>, H::Out, C::Error>
where 'x: 'key
{
let mut handle = handle;
loop {
let (mid, child) = match *handle {
NodeHandle::Hash(ref hash) => return Lookup{
db: &*self.db,
query: DBValue::from_slice,
hash: hash.clone(),
marker: PhantomData::<C>,
}.look_up(partial),
NodeHandle::InMemory(ref handle) => match self.storage[handle] {
Node::Empty => return Ok(None),
Node::Leaf(ref key, ref value) => {
if NibbleSlice::from_encoded(key).0 == partial {
return Ok(Some(DBValue::from_slice(value)));
} else {
return Ok(None);
}
}
Node::Extension(ref slice, ref child) => {
let slice = NibbleSlice::from_encoded(slice).0;
if partial.starts_with(&slice) {
(slice.len(), child)
} else {
return Ok(None);
}
}
Node::Branch(ref children, ref value) => {
if partial.is_empty() {
return Ok(value.as_ref().map(|v| DBValue::from_slice(v)));
} else {
let idx = partial.at(0);
match children[idx as usize].as_ref() {
Some(child) => (1, child),
None => return Ok(None),
}
}
}
}
};
partial = partial.mid(mid);
handle = child;
}
}
/// insert a key-value pair into the trie, creating new nodes if necessary.
fn insert_at(&mut self, handle: NodeHandle<H::Out>, partial: NibbleSlice, value: DBValue, old_val: &mut Option<DBValue>) -> Result<(StorageHandle, bool), H::Out, C::Error> {
let h = match handle {
NodeHandle::InMemory(h) => h,
NodeHandle::Hash(h) => self.cache(h)?,
};
let stored = self.storage.destroy(h);
let (new_stored, changed) = self.inspect(stored, move |trie, stored| {
trie.insert_inspector(stored, partial, value, old_val).map(|a| a.into_action())
})?.expect("Insertion never deletes.");
Ok((self.storage.alloc(new_stored), changed))
}
/// the insertion inspector.
fn insert_inspector(&mut self, node: Node<H::Out>, partial: NibbleSlice, value: DBValue, old_val: &mut Option<DBValue>) -> Result<InsertAction<H::Out>, H::Out, C::Error> {
trace!(target: "trie", "augmented (partial: {:?}, value: {:?})", partial, value.pretty());
Ok(match node {
Node::Empty => {
trace!(target: "trie", "empty: COMPOSE");
InsertAction::Replace(Node::Leaf(partial.encoded(true), value))
}
Node::Branch(mut children, stored_value) => {
trace!(target: "trie", "branch: ROUTE,AUGMENT");
if partial.is_empty() {
let unchanged = stored_value.as_ref() == Some(&value);
let branch = Node::Branch(children, Some(value));
*old_val = stored_value;
match unchanged {
true => InsertAction::Restore(branch),
false => InsertAction::Replace(branch),
}
} else {
let idx = partial.at(0) as usize;
let partial = partial.mid(1);
if let Some(child) = children[idx].take() {
// original had something there. recurse down into it.
let (new_child, changed) = self.insert_at(child, partial, value, old_val)?;
children[idx] = Some(new_child.into());
if !changed {
// the new node we composed didn't change. that means our branch is untouched too.
return Ok(InsertAction::Restore(Node::Branch(children, stored_value)));
}
} else {
// original had nothing there. compose a leaf.
let leaf = self.storage.alloc(Stored::New(Node::Leaf(partial.encoded(true), value)));
children[idx] = Some(leaf.into());
}
InsertAction::Replace(Node::Branch(children, stored_value))
}
}
Node::Leaf(encoded, stored_value) => {
let existing_key = NibbleSlice::from_encoded(&encoded).0;
let cp = partial.common_prefix(&existing_key);
if cp == existing_key.len() && cp == partial.len() {
trace!(target: "trie", "equivalent-leaf: REPLACE");
// equivalent leaf.
let unchanged = stored_value == value;
*old_val = Some(stored_value);
match unchanged {
// unchanged. restore
true => InsertAction::Restore(Node::Leaf(encoded.clone(), value)),
false => InsertAction::Replace(Node::Leaf(encoded.clone(), value)),
}
} else if cp == 0 {
trace!(target: "trie", "no-common-prefix, not-both-empty (exist={:?}; new={:?}): TRANSMUTE,AUGMENT", existing_key.len(), partial.len());
// one of us isn't empty: transmute to branch here
let mut children = empty_children();
let branch = if existing_key.is_empty() {
// always replace since branch isn't leaf.
Node::Branch(children, Some(stored_value))
} else {
let idx = existing_key.at(0) as usize;
let new_leaf = Node::Leaf(existing_key.mid(1).encoded(true), stored_value);
children[idx] = Some(self.storage.alloc(Stored::New(new_leaf)).into());
Node::Branch(children, None)
};
// always replace because whatever we get out here is not the branch we started with.
let branch_action = self.insert_inspector(branch, partial, value, old_val)?.unwrap_node();
InsertAction::Replace(branch_action)
} else if cp == existing_key.len() {
trace!(target: "trie", "complete-prefix (cp={:?}): AUGMENT-AT-END", cp);
// fully-shared prefix for an extension.
// make a stub branch and an extension.
let branch = Node::Branch(empty_children(), Some(stored_value));
// augment the new branch.
let branch = self.insert_inspector(branch, partial.mid(cp), value, old_val)?.unwrap_node();
// always replace since we took a leaf and made an extension.
let branch_handle = self.storage.alloc(Stored::New(branch)).into();
InsertAction::Replace(Node::Extension(existing_key.encoded(false), branch_handle))
} else {
trace!(target: "trie", "partially-shared-prefix (exist={:?}; new={:?}; cp={:?}): AUGMENT-AT-END", existing_key.len(), partial.len(), cp);
// partially-shared prefix for an extension.
// start by making a leaf.
let low = Node::Leaf(existing_key.mid(cp).encoded(true), stored_value);
// augment it. this will result in the Leaf -> cp == 0 routine,
// which creates a branch.
let augmented_low = self.insert_inspector(low, partial.mid(cp), value, old_val)?.unwrap_node();
// make an extension using it. this is a replacement.
InsertAction::Replace(Node::Extension(
existing_key.encoded_leftmost(cp, false),
self.storage.alloc(Stored::New(augmented_low)).into()
))
}
}
Node::Extension(encoded, child_branch) => {
let existing_key = NibbleSlice::from_encoded(&encoded).0;
let cp = partial.common_prefix(&existing_key);
if cp == 0 {
trace!(target: "trie", "no-common-prefix, not-both-empty (exist={:?}; new={:?}): TRANSMUTE,AUGMENT", existing_key.len(), partial.len());
// partial isn't empty: make a branch here
// extensions may not have empty partial keys.
assert!(!existing_key.is_empty());
let idx = existing_key.at(0) as usize;
let mut children = empty_children();
children[idx] = if existing_key.len() == 1 {
// direct extension, just replace.
Some(child_branch)
} else {
// more work required after branching.
let ext = Node::Extension(existing_key.mid(1).encoded(false), child_branch);
Some(self.storage.alloc(Stored::New(ext)).into())
};
// continue inserting.
let branch_action = self.insert_inspector(Node::Branch(children, None), partial, value, old_val)?.unwrap_node();
InsertAction::Replace(branch_action)
} else if cp == existing_key.len() {
trace!(target: "trie", "complete-prefix (cp={:?}): AUGMENT-AT-END", cp);
// fully-shared prefix.
// insert into the child node.
let (new_child, changed) = self.insert_at(child_branch, partial.mid(cp), value, old_val)?;
let new_ext = Node::Extension(existing_key.encoded(false), new_child.into());
// if the child branch wasn't changed, meaning this extension remains the same.
match changed {
true => InsertAction::Replace(new_ext),
false => InsertAction::Restore(new_ext),
}
} else {
trace!(target: "trie", "partially-shared-prefix (exist={:?}; new={:?}; cp={:?}): AUGMENT-AT-END", existing_key.len(), partial.len(), cp);
// partially-shared.
let low = Node::Extension(existing_key.mid(cp).encoded(false), child_branch);
// augment the extension. this will take the cp == 0 path, creating a branch.
let augmented_low = self.insert_inspector(low, partial.mid(cp), value, old_val)?.unwrap_node();
// always replace, since this extension is not the one we started with.
// this is known because the partial key is only the common prefix.
InsertAction::Replace(Node::Extension(
existing_key.encoded_leftmost(cp, false),
self.storage.alloc(Stored::New(augmented_low)).into()
))
}
}
})
}
/// Remove a node from the trie based on key.
fn remove_at(&mut self, handle: NodeHandle<H::Out>, partial: NibbleSlice, old_val: &mut Option<DBValue>) -> Result<Option<(StorageHandle, bool)>, H::Out, C::Error> {
let stored = match handle {
NodeHandle::InMemory(h) => self.storage.destroy(h),
NodeHandle::Hash(h) => {
let handle = self.cache(h)?;
self.storage.destroy(handle)
}
};
let opt = self.inspect(stored, move |trie, node| trie.remove_inspector(node, partial, old_val))?;
Ok(opt.map(|(new, changed)| (self.storage.alloc(new), changed)))
}
/// the removal inspector
fn remove_inspector(&mut self, node: Node<H::Out>, partial: NibbleSlice, old_val: &mut Option<DBValue>) -> Result<Action<H::Out>, H::Out, C::Error> {
Ok(match (node, partial.is_empty()) {
(Node::Empty, _) => Action::Delete,
(Node::Branch(c, None), true) => Action::Restore(Node::Branch(c, None)),
(Node::Branch(children, Some(val)), true) => {
*old_val = Some(val);
// always replace since we took the value out.
Action::Replace(self.fix(Node::Branch(children, None))?)
}
(Node::Branch(mut children, value), false) => {
let idx = partial.at(0) as usize;
if let Some(child) = children[idx].take() {
trace!(target: "trie", "removing value out of branch child, partial={:?}", partial);
match self.remove_at(child, partial.mid(1), old_val)? {
Some((new, changed)) => {
children[idx] = Some(new.into());
let branch = Node::Branch(children, value);
match changed {
// child was changed, so we were too.
true => Action::Replace(branch),
// unchanged, so we are too.
false => Action::Restore(branch),
}
}
None => {
// the child we took was deleted.
// the node may need fixing.
trace!(target: "trie", "branch child deleted, partial={:?}", partial);
Action::Replace(self.fix(Node::Branch(children, value))?)
}
}
} else {
// no change needed.
Action::Restore(Node::Branch(children, value))
}
}
(Node::Leaf(encoded, value), _) => {
if NibbleSlice::from_encoded(&encoded).0 == partial {
// this is the node we were looking for. Let's delete it.
*old_val = Some(value);
Action::Delete
} else {
// leaf the node alone.
trace!(target: "trie", "restoring leaf wrong partial, partial={:?}, existing={:?}", partial, NibbleSlice::from_encoded(&encoded).0);
Action::Restore(Node::Leaf(encoded, value))
}
}
(Node::Extension(encoded, child_branch), _) => {
let (cp, existing_len) = {
let existing_key = NibbleSlice::from_encoded(&encoded).0;
(existing_key.common_prefix(&partial), existing_key.len())
};
if cp == existing_len {
// try to remove from the child branch.
trace!(target: "trie", "removing from extension child, partial={:?}", partial);
match self.remove_at(child_branch, partial.mid(cp), old_val)? {
Some((new_child, changed)) => {
let new_child = new_child.into();
// if the child branch was unchanged, then the extension is too.
// otherwise, this extension may need fixing.
match changed {
true => Action::Replace(self.fix(Node::Extension(encoded, new_child))?),
false => Action::Restore(Node::Extension(encoded, new_child)),
}
}
None => {
// the whole branch got deleted.
// that means that this extension is useless.
Action::Delete
}
}
} else {
// partway through an extension -- nothing to do here.
Action::Restore(Node::Extension(encoded, child_branch))
}
}
})
}
/// Given a node which may be in an _invalid state_, fix it such that it is then in a valid
/// state.
///
/// _invalid state_ means:
/// - Branch node where there is only a single entry;
/// - Extension node followed by anything other than a Branch node.
fn fix(&mut self, node: Node<H::Out>) -> Result<Node<H::Out>, H::Out, C::Error> {
match node {
Node::Branch(mut children, value) => {
// if only a single value, transmute to leaf/extension and feed through fixed.
#[derive(Debug)]
enum UsedIndex {
None,
One(u8),
Many,
};
let mut used_index = UsedIndex::None;
for i in 0..16 {
match (children[i].is_none(), &used_index) {
(false, &UsedIndex::None) => used_index = UsedIndex::One(i as u8),
(false, &UsedIndex::One(_)) => {
used_index = UsedIndex::Many;
break;
}
_ => continue,
}
}
match (used_index, value) {
(UsedIndex::None, None) => panic!("Branch with no subvalues. Something went wrong."),
(UsedIndex::One(a), None) => {
// only one onward node. make an extension.
let new_partial = NibbleSlice::new_offset(&[a], 1).encoded(false);
let child = children[a as usize].take().expect("used_index only set if occupied; qed");
let new_node = Node::Extension(new_partial, child);
self.fix(new_node)
}
(UsedIndex::None, Some(value)) => {
// make a leaf.
trace!(target: "trie", "fixing: branch -> leaf");
Ok(Node::Leaf(NibbleSlice::new(&[]).encoded(true), value))
}
(_, value) => {
// all is well.
trace!(target: "trie", "fixing: restoring branch");
Ok(Node::Branch(children, value))
}
}
}
Node::Extension(partial, child) => {
let stored = match child {
NodeHandle::InMemory(h) => self.storage.destroy(h),
NodeHandle::Hash(h) => {
let handle = self.cache(h)?;
self.storage.destroy(handle)
}
};
let (child_node, maybe_hash) = match stored {
Stored::New(node) => (node, None),
Stored::Cached(node, hash) => (node, Some(hash))
};
match child_node {
Node::Extension(sub_partial, sub_child) => {
// combine with node below.
if let Some(hash) = maybe_hash {
// delete the cached child since we are going to replace it.
self.death_row.insert(hash);
}
let partial = NibbleSlice::from_encoded(&partial).0;
let sub_partial = NibbleSlice::from_encoded(&sub_partial).0;
let new_partial = NibbleSlice::new_composed(&partial, &sub_partial);
trace!(target: "trie", "fixing: extension combination. new_partial={:?}", new_partial);
self.fix(Node::Extension(new_partial.encoded(false), sub_child))
}
Node::Leaf(sub_partial, value) => {
// combine with node below.
if let Some(hash) = maybe_hash {
// delete the cached child since we are going to replace it.
self.death_row.insert(hash);
}
let partial = NibbleSlice::from_encoded(&partial).0;
let sub_partial = NibbleSlice::from_encoded(&sub_partial).0;
let new_partial = NibbleSlice::new_composed(&partial, &sub_partial);
trace!(target: "trie", "fixing: extension -> leaf. new_partial={:?}", new_partial);
Ok(Node::Leaf(new_partial.encoded(true), value))
}
child_node => {
trace!(target: "trie", "fixing: restoring extension");
// reallocate the child node.
let stored = if let Some(hash) = maybe_hash {
Stored::Cached(child_node, hash)
} else {
Stored::New(child_node)
};
Ok(Node::Extension(partial, self.storage.alloc(stored).into()))
}
}
}
other => Ok(other), // only ext and branch need fixing.
}
}
/// Commit the in-memory changes to disk, freeing their storage and
/// updating the state root.
pub fn commit(&mut self) {
trace!(target: "trie", "Committing trie changes to db.");
// always kill all the nodes on death row.
trace!(target: "trie", "{:?} nodes to remove from db", self.death_row.len());
for hash in self.death_row.drain() {
self.db.remove(&hash);
}
let handle = match self.root_handle() {
NodeHandle::Hash(_) => return, // no changes necessary.
NodeHandle::InMemory(h) => h,
};
match self.storage.destroy(handle) {
Stored::New(node) => {
let encoded_root = node.into_encoded::<_, C, H>(|child| self.commit_child(child) );
*self.root = self.db.insert(&encoded_root[..]);
self.hash_count += 1;
trace!(target: "trie", "encoded root node: {:?}", (&encoded_root[..]).pretty());
self.root_handle = NodeHandle::Hash(*self.root);
}
Stored::Cached(node, hash) => {
// probably won't happen, but update the root and move on.
*self.root = hash;
self.root_handle = NodeHandle::InMemory(self.storage.alloc(Stored::Cached(node, hash)));
}
}
}
/// Commit a node by hashing it and writing it to the db. Returns a
/// `ChildReference` which in most cases carries a normal hash but for the
/// case where we can fit the actual data in the `Hasher`s output type, we
/// store the data inline. This function is used as the callback to the
/// `into_encoded` method of `Node`.
fn commit_child(&mut self, handle: NodeHandle<H::Out>) -> ChildReference<H::Out> {
match handle {
NodeHandle::Hash(hash) => ChildReference::Hash(hash),
NodeHandle::InMemory(storage_handle) => {
match self.storage.destroy(storage_handle) {
Stored::Cached(_, hash) => ChildReference::Hash(hash),
Stored::New(node) => {
let encoded = node.into_encoded::<_, C, H>(|node_handle| self.commit_child(node_handle) );
if encoded.len() >= H::LENGTH {
let hash = self.db.insert(&encoded[..]);
self.hash_count +=1;
ChildReference::Hash(hash)
} else {
// it's a small value, so we cram it into a `H::Out` and tag with length
let mut h = H::Out::default();
let len = encoded.len();
h.as_mut()[..len].copy_from_slice(&encoded[..len]);
ChildReference::Inline(h, len)
}
}
}
}
}
}
// a hack to get the root node's handle
fn root_handle(&self) -> NodeHandle<H::Out> {
match self.root_handle {
NodeHandle::Hash(h) => NodeHandle::Hash(h),
NodeHandle::InMemory(StorageHandle(x)) => NodeHandle::InMemory(StorageHandle(x)),
}
}
}
impl<'a, H, C> TrieMut<H, C> for TrieDBMut<'a, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
fn root(&mut self) -> &H::Out {
self.commit();
self.root
}
fn is_empty(&self) -> bool {
match self.root_handle {
NodeHandle::Hash(h) => h == C::HASHED_NULL_NODE,
NodeHandle::InMemory(ref h) => match self.storage[h] {
Node::Empty => true,
_ => false,
}
}
}
fn get<'x, 'key>(&'x self, key: &'key [u8]) -> Result<Option<DBValue>, H::Out, C::Error>
where 'x: 'key
{
self.lookup(NibbleSlice::new(key), &self.root_handle)
}
fn insert(&mut self, key: &[u8], value: &[u8]) -> Result<Option<DBValue>, H::Out, C::Error> {
if value.is_empty() { return self.remove(key) }
let mut old_val = None;
trace!(target: "trie", "insert: key={:?}, value={:?}", key.pretty(), value.pretty());
let root_handle = self.root_handle();
let (new_handle, changed) = self.insert_at(
root_handle,
NibbleSlice::new(key),
DBValue::from_slice(value),
&mut old_val,
)?;
trace!(target: "trie", "insert: altered trie={}", changed);
self.root_handle = NodeHandle::InMemory(new_handle);
Ok(old_val)
}
fn remove(&mut self, key: &[u8]) -> Result<Option<DBValue>, H::Out, C::Error> {
trace!(target: "trie", "remove: key={:?}", key.pretty());
let root_handle = self.root_handle();
let key = NibbleSlice::new(key);
let mut old_val = None;
match self.remove_at(root_handle, key, &mut old_val)? {
Some((handle, changed)) => {
trace!(target: "trie", "remove: altered trie={}", changed);
self.root_handle = NodeHandle::InMemory(handle);
}
None => {
trace!(target: "trie", "remove: obliterated trie");
self.root_handle = NodeHandle::Hash(C::HASHED_NULL_NODE);
*self.root = C::HASHED_NULL_NODE;
}
}
Ok(old_val)
}
}
impl<'a, H, C> Drop for TrieDBMut<'a, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
fn drop(&mut self) {
self.commit();
}
}
#[cfg(test)]
mod tests {
use bytes::ToPretty;
use hashdb::{Hasher, HashDB};
use keccak_hasher::KeccakHasher;
use memorydb::MemoryDB;
use rlp::{Decodable, Encodable};
use triehash::trie_root;
use standardmap::*;
use ethtrie::{TrieDBMut, RlpCodec, trie::{TrieMut, NodeCodec}};
use env_logger;
use ethereum_types::H256;
use DBValue;
fn populate_trie<'db, H, C>(
db: &'db mut HashDB<KeccakHasher, DBValue>,
root: &'db mut H256,
v: &[(Vec<u8>, Vec<u8>)]
) -> TrieDBMut<'db>
where
H: Hasher,
H::Out: Decodable + Encodable,
C: NodeCodec<H>,
{
let mut t = TrieDBMut::new(db, root);
for i in 0..v.len() {
let key: &[u8]= &v[i].0;
let val: &[u8] = &v[i].1;
t.insert(key, val).unwrap();
}
t
}
fn unpopulate_trie<'db>(t: &mut TrieDBMut<'db>, v: &[(Vec<u8>, Vec<u8>)]) {
for i in v {
let key: &[u8]= &i.0;
t.remove(key).unwrap();
}
}
#[test]
fn playpen() {
env_logger::init();
let mut seed = H256::new();
for test_i in 0..10 {
if test_i % 50 == 0 {
debug!("{:?} of 10000 stress tests done", test_i);
}
let x = StandardMap {
alphabet: Alphabet::Custom(b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_".to_vec()),
min_key: 5,
journal_key: 0,
value_mode: ValueMode::Index,
count: 100,
}.make_with(&mut seed);
let real = trie_root::<KeccakHasher, _, _, _>(x.clone());
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut memtrie = populate_trie::<_, RlpCodec>(&mut memdb, &mut root, &x);
memtrie.commit();
if *memtrie.root() != real {
println!("TRIE MISMATCH");
println!("");
println!("{:?} vs {:?}", memtrie.root(), real);
for i in &x {
println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), real);
unpopulate_trie(&mut memtrie, &x);
memtrie.commit();
if *memtrie.root() != RlpCodec::HASHED_NULL_NODE {
println!("- TRIE MISMATCH");
println!("");
println!("{:?} vs {:?}", memtrie.root(), real);
for i in &x {
println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), RlpCodec::HASHED_NULL_NODE);
}
}
#[test]
fn init() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
assert_eq!(*t.root(), RlpCodec::HASHED_NULL_NODE);
}
#[test]
fn insert_on_empty() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![ (vec![0x01u8, 0x23], vec![0x01u8, 0x23]) ]));
}
#[test]
fn remove_to_empty() {
let big_value = b"00000000000000000000000000000000";
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t1 = TrieDBMut::new(&mut memdb, &mut root);
t1.insert(&[0x01, 0x23], big_value).unwrap();
t1.insert(&[0x01, 0x34], big_value).unwrap();
let mut memdb2 = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root2 = H256::new();
let mut t2 = TrieDBMut::new(&mut memdb2, &mut root2);
t2.insert(&[0x01], big_value).unwrap();
t2.insert(&[0x01, 0x23], big_value).unwrap();
t2.insert(&[0x01, 0x34], big_value).unwrap();
t2.remove(&[0x01]).unwrap();
}
#[test]
fn insert_replace_root() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[0x01u8, 0x23], &[0x23u8, 0x45]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![ (vec![0x01u8, 0x23], vec![0x23u8, 0x45]) ]));
}
#[test]
fn insert_make_branch_root() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[0x11u8, 0x23], &[0x11u8, 0x23]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x11u8, 0x23], vec![0x11u8, 0x23])
]));
}
#[test]
fn insert_into_branch_root() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[0xf1u8, 0x23], &[0xf1u8, 0x23]).unwrap();
t.insert(&[0x81u8, 0x23], &[0x81u8, 0x23]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x81u8, 0x23], vec![0x81u8, 0x23]),
(vec![0xf1u8, 0x23], vec![0xf1u8, 0x23]),
]));
}
#[test]
fn insert_value_into_branch_root() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[], &[0x0]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![], vec![0x0]),
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
]));
}
#[test]
fn insert_split_leaf() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[0x01u8, 0x34], &[0x01u8, 0x34]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x01u8, 0x34], vec![0x01u8, 0x34]),
]));
}
#[test]
fn insert_split_extenstion() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01, 0x23, 0x45], &[0x01]).unwrap();
t.insert(&[0x01, 0xf3, 0x45], &[0x02]).unwrap();
t.insert(&[0x01, 0xf3, 0xf5], &[0x03]).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01, 0x23, 0x45], vec![0x01]),
(vec![0x01, 0xf3, 0x45], vec![0x02]),
(vec![0x01, 0xf3, 0xf5], vec![0x03]),
]));
}
#[test]
fn insert_big_value() {
let big_value0 = b"00000000000000000000000000000000";
let big_value1 = b"11111111111111111111111111111111";
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], big_value0).unwrap();
t.insert(&[0x11u8, 0x23], big_value1).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01u8, 0x23], big_value0.to_vec()),
(vec![0x11u8, 0x23], big_value1.to_vec())
]));
}
#[test]
fn insert_duplicate_value() {
let big_value = b"00000000000000000000000000000000";
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], big_value).unwrap();
t.insert(&[0x11u8, 0x23], big_value).unwrap();
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(vec![
(vec![0x01u8, 0x23], big_value.to_vec()),
(vec![0x11u8, 0x23], big_value.to_vec())
]));
}
#[test]
fn test_at_empty() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let t = TrieDBMut::new(&mut memdb, &mut root);
assert_eq!(t.get(&[0x5]).unwrap(), None);
}
#[test]
fn test_at_one() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
assert_eq!(t.get(&[0x1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x1u8, 0x23]));
t.commit();
assert_eq!(t.get(&[0x1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x1u8, 0x23]));
}
#[test]
fn test_at_three() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
t.insert(&[0xf1u8, 0x23], &[0xf1u8, 0x23]).unwrap();
t.insert(&[0x81u8, 0x23], &[0x81u8, 0x23]).unwrap();
assert_eq!(t.get(&[0x01, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
assert_eq!(t.get(&[0xf1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0xf1u8, 0x23]));
assert_eq!(t.get(&[0x81, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x81u8, 0x23]));
assert_eq!(t.get(&[0x82, 0x23]).unwrap(), None);
t.commit();
assert_eq!(t.get(&[0x01, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
assert_eq!(t.get(&[0xf1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0xf1u8, 0x23]));
assert_eq!(t.get(&[0x81, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x81u8, 0x23]));
assert_eq!(t.get(&[0x82, 0x23]).unwrap(), None);
}
#[test]
fn stress() {
let mut seed = H256::new();
for _ in 0..50 {
let x = StandardMap {
alphabet: Alphabet::Custom(b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_".to_vec()),
min_key: 5,
journal_key: 0,
value_mode: ValueMode::Index,
count: 4,
}.make_with(&mut seed);
let real = trie_root::<KeccakHasher, _, _, _>(x.clone());
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut memtrie = populate_trie::<_, RlpCodec>(&mut memdb, &mut root, &x);
let mut y = x.clone();
y.sort_by(|ref a, ref b| a.0.cmp(&b.0));
let mut memdb2 = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root2 = H256::new();
let mut memtrie_sorted = populate_trie::<_, RlpCodec>(&mut memdb2, &mut root2, &y);
if *memtrie.root() != real || *memtrie_sorted.root() != real {
println!("TRIE MISMATCH");
println!("");
println!("ORIGINAL... {:?}", memtrie.root());
for i in &x {
println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
println!("SORTED... {:?}", memtrie_sorted.root());
for i in &y {
println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), real);
assert_eq!(*memtrie_sorted.root(), real);
}
}
#[test]
fn test_trie_existing() {
let mut db = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
{
let mut t = TrieDBMut::new(&mut db, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
}
{
let _ = TrieDBMut::from_existing(&mut db, &mut root);
}
}
#[test]
fn insert_empty() {
let mut seed = H256::new();
let x = StandardMap {
alphabet: Alphabet::Custom(b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_".to_vec()),
min_key: 5,
journal_key: 0,
value_mode: ValueMode::Index,
count: 4,
}.make_with(&mut seed);
let mut db = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut db, &mut root);
for &(ref key, ref value) in &x {
t.insert(key, value).unwrap();
}
assert_eq!(*t.root(), trie_root::<KeccakHasher, _, _, _>(x.clone()));
for &(ref key, _) in &x {
t.insert(key, &[]).unwrap();
}
assert!(t.is_empty());
assert_eq!(*t.root(), RlpCodec::HASHED_NULL_NODE);
}
#[test]
fn return_old_values() {
let mut seed = H256::new();
let x = StandardMap {
alphabet: Alphabet::Custom(b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_".to_vec()),
min_key: 5,
journal_key: 0,
value_mode: ValueMode::Index,
count: 4,
}.make_with(&mut seed);
let mut db = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
let mut t = TrieDBMut::new(&mut db, &mut root);
for &(ref key, ref value) in &x {
assert!(t.insert(key, value).unwrap().is_none());
assert_eq!(t.insert(key, value).unwrap(), Some(DBValue::from_slice(value)));
}
for (key, value) in x {
assert_eq!(t.remove(&key).unwrap(), Some(DBValue::from_slice(&value)));
assert!(t.remove(&key).unwrap().is_none());
}
}
}
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