openethereum/util/src/trie/triedbmut.rs

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2016-12-11 19:31:31 +01:00
// Copyright 2015, 2016 Parity Technologies (UK) Ltd.
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// 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::{TrieError, TrieMut};
use super::lookup::Lookup;
use super::node::Node as RlpNode;
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use super::node::NodeKey;
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use ::{HashDB, H256};
use ::bytes::ToPretty;
use ::nibbleslice::NibbleSlice;
use ::rlp::{Rlp, RlpStream, View, Stream};
use ::sha3::SHA3_NULL_RLP;
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use hashdb::DBValue;
use elastic_array::ElasticArray1024;
use std::collections::{HashSet, VecDeque};
use std::mem;
use std::ops::Index;
// 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 {
/// Loaded into memory.
InMemory(StorageHandle),
/// Either a hash or an inline node
Hash(H256),
}
impl From<StorageHandle> for NodeHandle {
fn from(handle: StorageHandle) -> Self {
NodeHandle::InMemory(handle)
}
}
impl From<H256> for NodeHandle {
fn from(hash: H256) -> Self {
NodeHandle::Hash(hash)
}
}
fn empty_children() -> Box<[Option<NodeHandle>; 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 {
/// 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.
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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.
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Extension(NodeKey, NodeHandle),
/// A branch has up to 16 children and an optional value.
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Branch(Box<[Option<NodeHandle>; 16]>, Option<DBValue>)
}
impl Node {
// load an inline node into memory or get the hash to do the lookup later.
fn inline_or_hash(node: &[u8], db: &HashDB, storage: &mut NodeStorage) -> NodeHandle {
let r = Rlp::new(node);
if r.is_data() && r.size() == 32 {
NodeHandle::Hash(r.as_val::<H256>())
} else {
let child = Node::from_rlp(node, db, storage);
NodeHandle::InMemory(storage.alloc(Stored::New(child)))
}
}
// decode a node from rlp without getting its children.
fn from_rlp(rlp: &[u8], db: &HashDB, storage: &mut NodeStorage) -> Self {
match RlpNode::decoded(rlp) {
RlpNode::Empty => Node::Empty,
RlpNode::Leaf(k, v) => Node::Leaf(k.encoded(true), DBValue::from_slice(&v)),
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RlpNode::Extension(key, cb) => {
Node::Extension(key.encoded(false), Self::inline_or_hash(cb, db, storage))
}
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RlpNode::Branch(children_rlp, val) => {
let mut children = empty_children();
for i in 0..16 {
let raw = children_rlp[i];
let child_rlp = Rlp::new(raw);
if !child_rlp.is_empty() {
children[i] = Some(Self::inline_or_hash(raw, db, storage));
}
}
Node::Branch(children, val.map(DBValue::from_slice))
}
}
}
// encode a node to RLP
// TODO: parallelize
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fn into_rlp<F>(self, mut child_cb: F) -> ElasticArray1024<u8>
where F: FnMut(NodeHandle, &mut RlpStream)
{
match self {
Node::Empty => {
let mut stream = RlpStream::new();
stream.append_empty_data();
stream.drain()
}
Node::Leaf(partial, value) => {
let mut stream = RlpStream::new_list(2);
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stream.append(&&*partial);
stream.append(&&*value);
stream.drain()
}
Node::Extension(partial, child) => {
let mut stream = RlpStream::new_list(2);
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stream.append(&&*partial);
child_cb(child, &mut stream);
stream.drain()
}
Node::Branch(mut children, value) => {
let mut stream = RlpStream::new_list(17);
for child in children.iter_mut().map(Option::take) {
if let Some(handle) = child {
child_cb(handle, &mut stream);
} else {
stream.append_empty_data();
}
}
if let Some(value) = value {
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stream.append(&&*value);
} else {
stream.append_empty_data();
}
stream.drain()
}
}
}
}
// post-inspect action.
enum Action {
// Replace a node with a new one.
Replace(Node),
// Restore the original node. This trusts that the node is actually the original.
Restore(Node),
// if it is a new node, just clears the storage.
Delete,
}
// post-insert action. Same as action without delete
enum InsertAction {
// Replace a node with a new one.
Replace(Node),
// Restore the original node.
Restore(Node),
}
impl InsertAction {
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fn into_action(self) -> Action {
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 {
match self {
InsertAction::Replace(n) | InsertAction::Restore(n) => n,
}
}
}
// What kind of node is stored here.
enum Stored {
// A new node.
New(Node),
// A cached node, loaded from the DB.
Cached(Node, H256),
}
/// Compact and cache-friendly storage for Trie nodes.
struct NodeStorage {
nodes: Vec<Stored>,
free_indices: VecDeque<usize>,
}
impl NodeStorage {
/// 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) -> 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 {
let idx = handle.0;
self.free_indices.push_back(idx);
mem::replace(&mut self.nodes[idx], Stored::New(Node::Empty))
}
}
impl<'a> Index<&'a StorageHandle> for NodeStorage {
type Output = Node;
fn index(&self, handle: &'a StorageHandle) -> &Node {
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 ethcore_util as util;
///
/// use util::trie::*;
/// use util::hashdb::*;
/// use util::memorydb::*;
/// use util::hash::*;
///
/// fn main() {
/// let mut memdb = MemoryDB::new();
/// let mut root = H256::new();
/// let mut t = TrieDBMut::new(&mut memdb, &mut root);
/// assert!(t.is_empty());
/// assert_eq!(*t.root(), ::util::sha3::SHA3_NULL_RLP);
/// t.insert(b"foo", b"bar").unwrap();
/// assert!(t.contains(b"foo").unwrap());
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/// 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> {
storage: NodeStorage,
db: &'a mut HashDB,
root: &'a mut H256,
root_handle: NodeHandle,
death_row: HashSet<H256>,
/// The number of hash operations this trie has performed.
/// Note that none are performed until changes are committed.
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pub hash_count: usize,
}
impl<'a> TrieDBMut<'a> {
/// Create a new trie with backing database `db` and empty `root`.
pub fn new(db: &'a mut HashDB, root: &'a mut H256) -> Self {
*root = SHA3_NULL_RLP;
let root_handle = NodeHandle::Hash(SHA3_NULL_RLP);
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TrieDBMut {
storage: NodeStorage::empty(),
db: db,
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root: root,
root_handle: root_handle,
death_row: HashSet::new(),
hash_count: 0,
}
}
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/// 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, root: &'a mut H256) -> super::Result<Self> {
if !db.contains(root) {
return Err(Box::new(TrieError::InvalidStateRoot(*root)));
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}
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,
})
}
/// Get the backing database.
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pub fn db(&self) -> &HashDB {
self.db
}
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/// Get the backing database mutably.
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pub fn db_mut(&mut self) -> &mut HashDB {
self.db
}
// cache a node by hash
fn cache(&mut self, hash: H256) -> super::Result<StorageHandle> {
let node_rlp = self.db.get(&hash).ok_or_else(|| Box::new(TrieError::IncompleteDatabase(hash)))?;
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let node = Node::from_rlp(&node_rlp, &*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, inspector: F) -> super::Result<Option<(Stored, bool)>>
where F: FnOnce(&mut Self, Node) -> super::Result<Action> {
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
}
},
})
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}
// walk the trie, attempting to find the key's node.
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fn lookup<'x, 'key>(&'x self, partial: NibbleSlice<'key>, handle: &NodeHandle) -> super::Result<Option<DBValue>>
where 'x: 'key
{
match *handle {
NodeHandle::Hash(ref hash) => Lookup {
db: &*self.db,
query: DBValue::from_slice,
hash: hash.clone(),
}.look_up(partial),
NodeHandle::InMemory(ref handle) => match self.storage[handle] {
Node::Empty => Ok(None),
Node::Leaf(ref key, ref value) => {
if NibbleSlice::from_encoded(key).0 == partial {
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Ok(Some(DBValue::from_slice(value)))
} else {
Ok(None)
}
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}
Node::Extension(ref slice, ref child) => {
let slice = NibbleSlice::from_encoded(slice).0;
if partial.starts_with(&slice) {
self.lookup(partial.mid(slice.len()), child)
} else {
Ok(None)
}
}
Node::Branch(ref children, ref value) => {
if partial.is_empty() {
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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) => self.lookup(partial.mid(1), child),
None => Ok(None),
}
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}
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}
}
}
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}
/// insert a key, value pair into the trie, creating new nodes if necessary.
fn insert_at(&mut self, handle: NodeHandle, partial: NibbleSlice, value: DBValue, old_val: &mut Option<DBValue>)
-> super::Result<(StorageHandle, bool)>
{
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))
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}
/// the insertion inspector.
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#[cfg_attr(feature = "dev", allow(cyclomatic_complexity))]
fn insert_inspector(&mut self, node: Node, partial: NibbleSlice, value: DBValue, old_val: &mut Option<DBValue>)
-> super::Result<InsertAction>
{
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()
))
}
}
})
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}
/// Remove a node from the trie based on key.
fn remove_at(&mut self, handle: NodeHandle, partial: NibbleSlice, old_val: &mut Option<DBValue>)
-> super::Result<Option<(StorageHandle, bool)>>
{
let stored = match handle {
NodeHandle::InMemory(h) => self.storage.destroy(h),
NodeHandle::Hash(h) => {
let handle = self.cache(h)?;
self.storage.destroy(handle)
}
};
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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)))
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}
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/// the removal inspector
fn remove_inspector(&mut self, node: Node, partial: NibbleSlice, old_val: &mut Option<DBValue>) -> super::Result<Action> {
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))
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}
}
(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
}
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}
} else {
// partway through an extension -- nothing to do here.
Action::Restore(Node::Extension(encoded, child_branch))
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}
}
})
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}
/// Given a node which may be in an _invalid state_, fix it such that it is then in a valid
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/// 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) -> super::Result<Node> {
match node {
Node::Branch(mut children, value) => {
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// if only a single value, transmute to leaf/extension and feed through fixed.
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#[derive(Debug)]
enum UsedIndex {
None,
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One(u8),
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Many,
};
let mut used_index = UsedIndex::None;
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for i in 0..16 {
match (children[i].is_none(), &used_index) {
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(false, &UsedIndex::None) => used_index = UsedIndex::One(i as u8),
(false, &UsedIndex::One(_)) => {
used_index = UsedIndex::Many;
break;
}
_ => continue,
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}
}
match (used_index, value) {
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(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))
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}
}
}
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()))
}
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}
}
other => Ok(other), // only ext and branch need fixing.
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}
}
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/// 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) => {
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let root_rlp = node.into_rlp(|child, stream| self.commit_node(child, stream));
*self.root = self.db.insert(&root_rlp[..]);
self.hash_count += 1;
trace!(target: "trie", "root node rlp: {:?}", (&root_rlp[..]).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)));
}
}
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}
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/// commit a node, hashing it, committing it to the db,
/// and writing it to the rlp stream as necessary.
fn commit_node(&mut self, handle: NodeHandle, stream: &mut RlpStream) {
match handle {
NodeHandle::Hash(h) => stream.append(&h),
NodeHandle::InMemory(h) => match self.storage.destroy(h) {
Stored::Cached(_, h) => stream.append(&h),
Stored::New(node) => {
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let node_rlp = node.into_rlp(|child, stream| self.commit_node(child, stream));
if node_rlp.len() >= 32 {
let hash = self.db.insert(&node_rlp[..]);
self.hash_count += 1;
stream.append(&hash)
} else {
stream.append_raw(&node_rlp, 1)
}
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}
}
};
}
// a hack to get the root node's handle
fn root_handle(&self) -> NodeHandle {
match self.root_handle {
NodeHandle::Hash(h) => NodeHandle::Hash(h),
NodeHandle::InMemory(StorageHandle(x)) => NodeHandle::InMemory(StorageHandle(x)),
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}
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}
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}
impl<'a> TrieMut for TrieDBMut<'a> {
fn root(&mut self) -> &H256 {
self.commit();
self.root
}
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fn is_empty(&self) -> bool {
match self.root_handle {
NodeHandle::Hash(h) => h == SHA3_NULL_RLP,
NodeHandle::InMemory(ref h) => match self.storage[h] {
Node::Empty => true,
_ => false,
}
}
}
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fn get<'x, 'key>(&'x self, key: &'key [u8]) -> super::Result<Option<DBValue>> where 'x: 'key {
self.lookup(NibbleSlice::new(key), &self.root_handle)
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}
fn insert(&mut self, key: &[u8], value: &[u8]) -> super::Result<Option<DBValue>> {
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)
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}
fn remove(&mut self, key: &[u8]) -> super::Result<Option<DBValue>> {
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(SHA3_NULL_RLP);
*self.root = SHA3_NULL_RLP;
}
}
Ok(old_val)
}
}
impl<'a> Drop for TrieDBMut<'a> {
fn drop(&mut self) {
self.commit();
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}
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}
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#[cfg(test)]
mod tests {
use triehash::trie_root;
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use hash::*;
use hashdb::*;
use memorydb::*;
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use super::*;
use bytes::ToPretty;
use sha3::SHA3_NULL_RLP;
use super::super::TrieMut;
use super::super::standardmap::*;
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fn populate_trie<'db>(db: &'db mut HashDB, root: &'db mut H256, v: &[(Vec<u8>, Vec<u8>)]) -> TrieDBMut<'db> {
let mut t = TrieDBMut::new(db, root);
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for i in 0..v.len() {
let key: &[u8]= &v[i].0;
let val: &[u8] = &v[i].1;
t.insert(key, val).unwrap();
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}
t
}
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fn unpopulate_trie<'db>(t: &mut TrieDBMut<'db>, v: &[(Vec<u8>, Vec<u8>)]) {
for i in v {
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let key: &[u8]= &i.0;
t.remove(key).unwrap();
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}
}
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#[test]
fn playpen() {
::log::init_log();
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let mut seed = H256::new();
for test_i in 0..10 {
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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);
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let real = trie_root(x.clone());
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut memtrie = populate_trie(&mut memdb, &mut root, &x);
memtrie.commit();
if *memtrie.root() != real {
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println!("TRIE MISMATCH");
println!("");
println!("{:?} vs {:?}", memtrie.root(), real);
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for i in &x {
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println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), real);
unpopulate_trie(&mut memtrie, &x);
memtrie.commit();
if *memtrie.root() != SHA3_NULL_RLP {
println!("- TRIE MISMATCH");
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println!("");
println!("{:?} vs {:?}", memtrie.root(), real);
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for i in &x {
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println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), SHA3_NULL_RLP);
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}
}
#[test]
fn init() {
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
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assert_eq!(*t.root(), SHA3_NULL_RLP);
}
#[test]
fn insert_on_empty() {
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
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assert_eq!(*t.root(), trie_root(vec![ (vec![0x01u8, 0x23], vec![0x01u8, 0x23]) ]));
}
#[test]
fn remove_to_empty() {
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let big_value = b"00000000000000000000000000000000";
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut t1 = TrieDBMut::new(&mut memdb, &mut root);
t1.insert(&[0x01, 0x23], &big_value.to_vec()).unwrap();
t1.insert(&[0x01, 0x34], &big_value.to_vec()).unwrap();
let mut memdb2 = MemoryDB::new();
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let mut root2 = H256::new();
let mut t2 = TrieDBMut::new(&mut memdb2, &mut root2);
t2.insert(&[0x01], &big_value.to_vec()).unwrap();
t2.insert(&[0x01, 0x23], &big_value.to_vec()).unwrap();
t2.insert(&[0x01, 0x34], &big_value.to_vec()).unwrap();
t2.remove(&[0x01]).unwrap();
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}
#[test]
fn insert_replace_root() {
let mut memdb = MemoryDB::new();
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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();
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assert_eq!(*t.root(), trie_root(vec![ (vec![0x01u8, 0x23], vec![0x23u8, 0x45]) ]));
}
#[test]
fn insert_make_branch_root() {
let mut memdb = MemoryDB::new();
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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();
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assert_eq!(*t.root(), trie_root(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x11u8, 0x23], vec![0x11u8, 0x23])
]));
}
#[test]
fn insert_into_branch_root() {
let mut memdb = MemoryDB::new();
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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();
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assert_eq!(*t.root(), trie_root(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::new();
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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();
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assert_eq!(*t.root(), trie_root(vec![
(vec![], vec![0x0]),
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
]));
}
#[test]
fn insert_split_leaf() {
let mut memdb = MemoryDB::new();
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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();
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assert_eq!(*t.root(), trie_root(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x01u8, 0x34], vec![0x01u8, 0x34]),
]));
}
#[test]
fn insert_split_extenstion() {
let mut memdb = MemoryDB::new();
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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();
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assert_eq!(*t.root(), trie_root(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::new();
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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();
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assert_eq!(*t.root(), trie_root(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::new();
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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();
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assert_eq!(*t.root(), trie_root(vec![
(vec![0x01u8, 0x23], big_value.to_vec()),
(vec![0x11u8, 0x23], big_value.to_vec())
]));
}
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#[test]
fn test_at_empty() {
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let t = TrieDBMut::new(&mut memdb, &mut root);
assert_eq!(t.get(&[0x5]), Ok(None));
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}
#[test]
fn test_at_one() {
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
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assert_eq!(t.get(&[0x1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x1u8, 0x23]));
t.commit();
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assert_eq!(t.get(&[0x1, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x1u8, 0x23]));
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}
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#[test]
fn test_at_three() {
let mut memdb = MemoryDB::new();
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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();
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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]), Ok(None));
t.commit();
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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]), Ok(None));
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}
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#[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);
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let real = trie_root(x.clone());
let mut memdb = MemoryDB::new();
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let mut root = H256::new();
let mut memtrie = populate_trie(&mut memdb, &mut root, &x);
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let mut y = x.clone();
y.sort_by(|ref a, ref b| a.0.cmp(&b.0));
let mut memdb2 = MemoryDB::new();
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let mut root2 = H256::new();
let mut memtrie_sorted = populate_trie(&mut memdb2, &mut root2, &y);
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if *memtrie.root() != real || *memtrie_sorted.root() != real {
println!("TRIE MISMATCH");
println!("");
println!("ORIGINAL... {:?}", memtrie.root());
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for i in &x {
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println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
println!("SORTED... {:?}", memtrie_sorted.root());
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for i in &y {
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println!("{:?} -> {:?}", i.0.pretty(), i.1.pretty());
}
}
assert_eq!(*memtrie.root(), real);
assert_eq!(*memtrie_sorted.root(), real);
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}
}
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#[test]
fn test_trie_existing() {
let mut root = H256::new();
let mut db = MemoryDB::new();
{
let mut t = TrieDBMut::new(&mut db, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
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}
{
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let _ = TrieDBMut::from_existing(&mut db, &mut root);
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}
}
#[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::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(x.clone()));
for &(ref key, _) in &x {
t.insert(key, &[]).unwrap();
}
assert!(t.is_empty());
assert_eq!(*t.root(), SHA3_NULL_RLP);
}
#[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::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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}