openethereum/src/trie.rs

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Rust
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use memorydb::*;
use sha3::*;
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use hashdb::*;
use hash::*;
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use nibbleslice::*;
use bytes::*;
use rlp::*;
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use log::*;
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pub const NULL_RLP: [u8; 1] = [0x80; 1];
pub const SHA3_NULL_RLP: H256 = H256( [0x56, 0xe8, 0x1f, 0x17, 0x1b, 0xcc, 0x55, 0xa6, 0xff, 0x83, 0x45, 0xe6, 0x92, 0xc0, 0xf8, 0x6e, 0x5b, 0x48, 0xe0, 0x1b, 0x99, 0x6c, 0xad, 0xc0, 0x01, 0x62, 0x2f, 0xb5, 0xe3, 0x63, 0xb4, 0x21] );
/*lazy_static! {
pub static ref NULL_RLP: Bytes = { let mut r = RlpStream::new(); r.append(&""); r.out().unwrap() };
pub static ref SHA3_NULL_RLP: H256 = { use sha3::Hashable; NULL_RLP.sha3() };
}*/
pub trait Trie {
fn root(&self) -> &H256;
fn is_empty(&self) -> bool { *self.root() == SHA3_NULL_RLP }
// TODO: consider returning &[u8]...
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fn contains(&self, key: &[u8]) -> bool;
fn at(&self, key: &[u8]) -> Option<&[u8]>;
fn insert(&mut self, key: &[u8], value: &[u8]);
fn remove(&mut self, key: &[u8]);
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}
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enum Operation {
New(H256, Bytes),
Delete(H256),
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}
struct Diff (Vec<Operation>);
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impl Diff {
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fn new() -> Diff { Diff(vec![]) }
/// Given the RLP that encodes a node, append a reference to that node `out` and leave `diff`
/// such that the reference is valid, once applied.
fn new_node(&mut self, rlp: Bytes, out: &mut RlpStream) {
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if (rlp.len() >= 32) {
let rlp_sha3 = rlp.sha3();
out.append(&rlp_sha3);
self.0.push(Operation::New(rlp_sha3, rlp));
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}
else {
out.append_raw(&rlp, 1);
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}
}
/// Given the RLP that encodes a now-unused node, leave `diff` in such a state that it is noted.
fn delete_node_sha3(&mut self, old_sha3: H256) {
self.0.push(Operation::Delete(old_sha3));
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}
fn delete_node(&mut self, old: &Rlp) {
if (old.is_data() && old.size() == 32) {
self.0.push(Operation::Delete(H256::decode(old)));
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}
}
fn replace_node(&mut self, old: &Rlp, rlp: Bytes, out: &mut RlpStream) {
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self.delete_node(old);
self.new_node(rlp, out);
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}
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}
pub struct TrieDB {
db: Box<HashDB>,
root: H256,
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}
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impl TrieDB {
pub fn new<T>(db: T) -> Self where T: HashDB + 'static { TrieDB{ db: Box::new(db), root: H256::new() } }
pub fn new_boxed(db_box: Box<HashDB>) -> Self { TrieDB{ db: db_box, root: H256::new() } }
pub fn new_memory() -> Self { TrieDB{ db: Box::new(MemoryDB::new()), root: H256::new() } }
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pub fn init(&mut self) { self.set_root_rlp(&NULL_RLP); }
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pub fn db(&self) -> &HashDB { self.db.as_ref() }
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fn set_root_rlp(&mut self, root_data: &[u8]) {
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self.db.kill(&self.root);
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self.root = self.db.insert(root_data);
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println!("set_root_rlp {:?} {:?}", root_data, self.root);
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}
fn apply(&mut self, diff: Diff) {
for d in diff.0.into_iter() {
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match d {
Operation::Delete(h) => {
trace!("TrieDB::apply --- {:?}", &h);
self.db.kill(&h);
},
Operation::New(h, d) => {
trace!("TrieDB::apply +++ {:?} -> {:?}", &h, &d);
self.db.emplace(h, d);
}
}
}
}
/*
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fn add(&mut self, key: &NibbleSlice, value: &[u8]) {
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// determine what the new root is, insert new nodes and remove old as necessary.
let todo: Diff = Diff::new();
let root_rlp = self.inject(self.db.lookup(&self.root).expect("Trie root not found!"), key, value, &mut todo);
self.apply(todo);
self.set_root_rlp(&root_rlp);
}
fn compose_raw(partial: &NibbleSlice, raw_payload: &[u8], bool is_leaf) -> Bytes {
println!("compose_raw {:?} {:?} {:?} ({:?})", partial, value, is_leaf, partial.encoded(is_leaf));
let mut s = RlpStream::new_list(2);
s.append(&partial.encoded(is_leaf));
s.append_raw(raw_payload, 1);
let r = s.out();
println!("output: -> {:?}", &r);
r
}
fn compose_leaf(partial: &NibbleSlice, value: &[u8]) -> Bytes {
println!("compose_leaf {:?} {:?} ({:?})", partial, value, partial.encoded(true));
let mut s = RlpStream::new_list(2);
s.append(&partial.encoded(true));
s.append(value);
let r = s.out();
println!("output: -> {:?}", &r);
r
}
fn compose_extension(partial: &NibbleSlice, raw_payload: &[u8]) -> Bytes {
Self::compose_raw(partial, raw_payload, false)
}
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/// Return the bytes encoding the node represented by `rlp`. It will be unlinked from
/// the trie.
fn take_node(&self, rlp: &Rlp, &mut diff) -> Bytes {
if (rlp.is_data()) {
Bytes::decode(rlp)
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}
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else {
let h = H256::decode(rlp);
let r = self.db.lookup(&h).expect("Trie root not found!").as_vec();
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diff.delete_node(h);
r
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}
}
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/// Transform an existing extension or leaf node plus a new partial/value to a two-entry branch.
///
/// **This operation will not insert the new node nor destroy the original.**
fn transmute_to_branch_and_inject(&self, orig_is_leaf: bool, orig_partial: &NibbleSlice, orig_raw_payload: &[u8], partial: &NibbleSlice, value: &[u8], diff: &mut Diff) -> Bytes {
let intermediate = match orig_is_leaf {
true => Self::transmute_leaf_to_branch(orig_partial, orig_raw_payload, diff),
false => Self::transmute_extension_to_branch(orig_partial, orig_raw_payload, diff),
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};
self.inject(&intermediate, partial, value, diff)
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// TODO: implement without having to make an intermediate representation.
}
/// Transform an existing extension or leaf node to an invalid single-entry branch.
///
/// **This operation will not insert the new node nor destroy the original.**
fn transmute_extension_to_branch(orig_partial: &NibbleSlice, orig_raw_payload: &[u8], diff: &mut Diff) -> Bytes {
let mut s = RLPStream::new_list(17);
assert!(!orig_partial.is_empty()); // extension nodes are not allowed to have empty partial keys.
let index = orig_partial.at(0);
// orig is extension - orig_payload is a node itself.
for i in 0..17 {
if index == i {
if orig_partial.len() > 1 {
// still need an extension
diff.new_node(compose_extension(orig_partial.mid(1), orig_raw_payload), s);
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} else {
// was an extension of length 1 - just redirect the payload into here.
s.append_raw(orig_payload.raw(), 1);
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}
} else {
s.append_null_data();
}
}
s.out()
}
fn transmute_leaf_to_branch(orig_partial: &NibbleSlice, orig_raw_payload: &[u8], diff: &mut Diff) -> Bytes {
let mut s = RLPStream::new_list(17);
let index = orig_partial.is_empty() ? 16 : orig_partial.at(0);
// orig is leaf - orig_payload is data representing the actual value.
for i in 0..17 {
if index == i {
// this is our node.
diff.new_node(compose_raw(orig_partial.mid(if i == 16 {0} else {1}), orig_raw_payload, true), s);
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} else {
s.append_null_data();
}
}
s.out()
}
/// Given a branch node's RLP `orig` together with a `partial` key and `value`, return the
/// RLP-encoded node that accomodates the trie with the new entry. Mutate `diff` so that
/// once applied the returned node is valid.
fn injected_into_branch(&self, orig: &Rlp, partial: &NibbleSlice, value: &[u8], diff: &mut Diff) -> Bytes {
RlpStream s;
let index = partial.is_empty() ? 16 : partial.at(0);
for i in 0..17 {
if index == i && {
// this is our node.
if (orig.at(i).is_empty()) {
// easy - original had empty slot.
diff.new_node(compose_leaf(partial.mid(if i == 16 {0} else {1}), value), s);
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} else if (i == 16) {
// leaf entry - just replace.
let new = compose_leaf(partial.mid(if i == 16 {0} else {1}), value);
diff.replace_node(orig.at(i).raw(), new, s),
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} else {
// harder - original has something there already
let new = self.inject(orig.at(i).raw(), partial.mid(1), value, diff);
diff.replace_node(orig.at(i).raw(), new, s)
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}
} else {
s.append_raw(orig.at(i).raw(), 1);
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}
}
s
}
fn inject_and_replace(&self, old: &[u8], old_sha3: H256, partial: &NibbleSlice, value: &[u8], diff: &mut Diff, out: &mut RlpStream) {
diff.new_node(self.inject(old, partial, value, diff), &mut out);
diff.delete_node(old, old_sha3);
}
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/// Determine the RLP of the node, assuming we're inserting `partial` into the
/// node currently of data `old`. This will *not* delete any hash of `old` from the database;
/// it will just return the new RLP that includes the new node.
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///
/// The database will be updated so as to make the returned RLP valid through inserting
/// and deleting nodes as necessary.
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///
/// **This operation will not insert the new node now destroy the original.**
fn inject(&self, old: &[u8], partial: &NibbleSlice, value: &[u8], diff: &mut Diff) -> Bytes {
// already have an extension. either fast_forward, cleve or transmute_to_branch.
let old_rlp = Rlp::new(old);
match old_rlp.prototype() {
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Prototype::List(17) => {
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// already have a branch. route and inject.
self.injected_into_branch(old_rlp, partial, value, diff)
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},
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Prototype::List(2) => {
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let their_key_rlp = old_rlp.at(0);
let (them, is_leaf) = NibbleSlice::from_encoded(their_key_rlp.data());
match partial.common_prefix(&them) {
0 if partial.is_empty() && them.is_empty() => {
// both empty: just replace.
compose_leaf(partial, value)
},
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0 => {
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// one of us isn't empty: transmute to branch here
transmute_to_branch_and_inject(is_leaf, them, old_rlp.at(1).raw())
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},
cp if cp == them.len() => {
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// fully-shared prefix for this extension:
// skip to the end of this extension and continue the inject there.
let n = self.take_node(old_rlp.at(1).raw());
let downstream_node = self.inject(&n, partial.mid(cp), value, diff);
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let mut s = RlpStream::new_list(2);
s.append_raw(old_rlp.at(0).raw(), 1);
diff.new_node(downstream_node, s);
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s.out()
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},
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cp => {
// partially-shared prefix for this extension:
// split into two extensions, high and low, pass the
// low through inject with the value before inserting the result
// into high to create the new.
// TODO: optimise by doing this without creating injected_low.
// low (farther from root)
let low = Self::compose_raw(them.mid(cp), old_rlp.at(1).raw(), is_leaf);
let injected_low = self.inject(&low, partial.mid(cp), value, diff);
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// high (closer to root)
let mut s = RlpStream::new_list(2);
s.append(them.encoded_leftmost(cp, false));
diff.new_node(injected_low, s);
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s.out()
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},
}
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},
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Prototype::Data(0) => {
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(Self::compose_leaf(partial, value, true), Diff::new())
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},
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_ => panic!("Invalid RLP for node."),
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}
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}
*/
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}
impl Trie for TrieDB {
fn root(&self) -> &H256 { &self.root }
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fn contains(&self, _key: &[u8]) -> bool {
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unimplemented!();
}
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fn at(&self, _key: &[u8]) -> Option<&[u8]> {
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unimplemented!();
}
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fn insert(&mut self, key: &[u8], value: &[u8]) {
unimplemented!();
// (self as &mut TrieDB).add(&NibbleSlice::new(key), value);
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}
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fn remove(&mut self, _key: &[u8]) {
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unimplemented!();
}
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}
#[test]
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fn playpen() {
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use overlaydb::*;
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use triehash::*;
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(&[1, 2, 3]).starts_with(&[1, 2]);
let mut t = TrieDB::new(OverlayDB::new_temp());
t.init();
assert_eq!(*t.root(), SHA3_NULL_RLP);
assert!(t.is_empty());
/*
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t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]);
assert_eq!(*t.root(), trie_root(vec![ (vec![1u8, 0x23], vec![1u8, 0x23]) ]));*/
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}