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Merge pull request #363 from ethcore/state

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Fixed an issue with forked counters
This commit is contained in:
Gav Wood 2016-02-07 22:46:57 +01:00
commit c55ff797a7
1 changed files with 65 additions and 24 deletions
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89
util/src/journaldb.rs
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@ -92,7 +92,6 @@ impl JournalDB {
/// Commit all recent insert operations and historical removals from the old era
/// to the backing database.
#[allow(cyclomatic_complexity)]
pub fn commit(&mut self, now: u64, id: &H256, end: Option<(u64, H256)>) -> Result<u32, UtilError> {
// journal format:
// [era, 0] => [ id, [insert_0, ...], [remove_0, ...] ]
@ -105,6 +104,17 @@ impl JournalDB {
// for each end_era that we journaled that we are no passing by,
// we remove all of its removes assuming it is canonical and all
// of its inserts otherwise.
//
// We also keep reference counters for each key inserted in the journal to handle
// the following cases where key K must not be deleted from the DB when processing removals :
// Given H is the journal size in eras, 0 <= C <= H.
// Key K is removed in era A(N) and re-inserted in canonical era B(N + C).
// Key K is removed in era A(N) and re-inserted in non-canonical era B`(N + C).
// Key K is added in non-canonical era A'(N) canonical B(N + C).
//
// The counter is encreased each time a key is inserted in the journal in the commit. The list of insertions
// is saved with the era record. When the era becomes end_era and goes out of journal the counter is decreased
// and the key is safe to delete.
// record new commit's details.
let batch = WriteBatch::new();
@ -125,6 +135,7 @@ impl JournalDB {
let mut r = RlpStream::new_list(3);
let inserts: Vec<H256> = self.overlay.keys().iter().filter(|&(_, &c)| c > 0).map(|(key, _)| key.clone()).collect();
// Increase counter for each inserted key no matter if the block is canonical or not.
for i in &inserts {
*counters.entry(i.clone()).or_insert(0) += 1;
}
@ -139,6 +150,8 @@ impl JournalDB {
if let Some((end_era, canon_id)) = end {
let mut index = 0usize;
let mut last;
let mut to_remove: Vec<H256> = Vec::new();
let mut canon_inserts: Vec<H256> = Vec::new();
while let Some(rlp_data) = try!(self.backing.get({
let mut r = RlpStream::new_list(2);
r.append(&end_era);
@ -146,39 +159,33 @@ impl JournalDB {
last = r.drain();
&last
})) {
let to_add;
let rlp = Rlp::new(&rlp_data);
{
to_add = rlp.val_at(1);
for i in &to_add {
let delete_counter = {
if let Some(mut cnt) = counters.get_mut(i) {
*cnt -= 1;
*cnt == 0
}
else { false }
};
if delete_counter {
counters.remove(i);
}
}
let inserts: Vec<H256> = rlp.val_at(1);
JournalDB::decrease_counters(&inserts, &mut counters);
// Collect keys to be removed. These are removed keys for canonical block, inserted for non-canonical
if canon_id == rlp.val_at(0) {
to_remove.extend(rlp.at(2).iter().map(|r| r.as_val::<H256>()));
canon_inserts = inserts;
}
let to_remove: Vec<H256> = if canon_id == rlp.val_at(0) {rlp.val_at(2)} else {to_add};
for i in &to_remove {
if !counters.contains_key(i) {
batch.delete(&i).expect("Low-level database error. Some issue with your hard disk?");
}
else {
to_remove.extend(inserts);
}
try!(batch.delete(&last));
trace!("JournalDB: delete journal for time #{}.{}, (canon was {}): {} entries", end_era, index, canon_id, to_remove.len());
index += 1;
}
let canon_inserts = canon_inserts.drain(..).collect::<HashSet<_>>();
// Purge removed keys if they are not referenced and not re-inserted in the canon commit
let mut deletes = 0;
for h in to_remove.iter().filter(|h| !counters.contains_key(h) && !canon_inserts.contains(h)) {
try!(batch.delete(&h));
deletes += 1;
}
try!(batch.put(&LAST_ERA_KEY, &encode(&end_era)));
trace!("JournalDB: delete journal for time #{}.{}, (canon was {}): {} entries", end_era, index, canon_id, deletes);
}
// Commit overlay insertions
let mut ret = 0u32;
let mut deletes = 0usize;
for i in self.overlay.drain().into_iter() {
@ -200,6 +207,23 @@ impl JournalDB {
Ok(ret)
}
// Decrease counters for given keys. Deletes obsolete counters
fn decrease_counters(keys: &[H256], counters: &mut HashMap<H256, i32>) {
for i in keys.iter() {
let delete_counter = {
if let Some(mut cnt) = counters.get_mut(i) {
*cnt -= 1;
*cnt == 0
}
else { false }
};
if delete_counter {
counters.remove(i);
}
}
}
fn payload(&self, key: &H256) -> Option<Bytes> {
self.backing.get(&key.bytes()).expect("Low-level database error. Some issue with your hard disk?").map(|v| v.to_vec())
}
@ -387,4 +411,21 @@ mod tests {
jdb.commit(3, &b"2".sha3(), Some((0, b"2".sha3()))).unwrap();
assert!(jdb.exists(&foo));
}
#[test]
fn fork_same_key() {
// history is 1
let mut jdb = JournalDB::new_temp();
jdb.commit(0, &b"0".sha3(), None).unwrap();
let foo = jdb.insert(b"foo");
jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
jdb.insert(b"foo");
jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
assert!(jdb.exists(&foo));
jdb.commit(2, &b"2a".sha3(), Some((1, b"1a".sha3()))).unwrap();
assert!(jdb.exists(&foo));
}
}