use hash_db::{HashDBRef, Hasher};
use super::{Result, DBValue, TrieDB, Trie, TrieDBIterator, TrieItem, TrieIterator, Query};
use node_codec::NodeCodec;
#[cfg(not(feature = "std"))]
use alloc::boxed::Box;
pub struct FatDB<'db, H, C>
where
H: Hasher + 'db,
C: NodeCodec<H>
{
raw: TrieDB<'db, H, C>,
}
impl<'db, H, C> FatDB<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
pub fn new(db: &'db HashDBRef<H, DBValue>, root: &'db H::Out) -> Result<Self, H::Out, C::Error> {
Ok(FatDB { raw: TrieDB::new(db, root)? })
}
pub fn db(&self) -> &HashDBRef<H, DBValue> { self.raw.db() }
}
impl<'db, H, C> Trie<H, C> for FatDB<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
fn root(&self) -> &H::Out { self.raw.root() }
fn contains(&self, key: &[u8]) -> Result<bool, H::Out, C::Error> {
self.raw.contains(H::hash(key).as_ref())
}
fn get_with<'a, 'key, Q: Query<H>>(&'a self, key: &'key [u8], query: Q) -> Result<Option<Q::Item>, H::Out, C::Error>
where 'a: 'key
{
self.raw.get_with(H::hash(key).as_ref(), query)
}
fn iter<'a>(&'a self) -> Result<Box<TrieIterator<H, C, Item = TrieItem<H::Out, C::Error>> + 'a>, <H as Hasher>::Out, C::Error> {
FatDBIterator::<H, C>::new(&self.raw).map(|iter| Box::new(iter) as Box<_>)
}
}
pub struct FatDBIterator<'db, H, C>
where
H: Hasher + 'db,
C: NodeCodec<H> + 'db
{
trie_iterator: TrieDBIterator<'db, H, C>,
trie: &'db TrieDB<'db, H, C>,
}
impl<'db, H, C> FatDBIterator<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
pub fn new(trie: &'db TrieDB<H, C>) -> Result<Self, H::Out, C::Error> {
Ok(FatDBIterator {
trie_iterator: TrieDBIterator::new(trie)?,
trie: trie,
})
}
}
impl<'db, H, C> TrieIterator<H, C> for FatDBIterator<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
fn seek(&mut self, key: &[u8]) -> Result<(), H::Out, C::Error> {
let hashed_key = H::hash(key);
self.trie_iterator.seek(hashed_key.as_ref())
}
}
impl<'db, H, C> Iterator for FatDBIterator<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
type Item = TrieItem<'db, H::Out, C::Error>;
fn next(&mut self) -> Option<Self::Item> {
self.trie_iterator.next()
.map(|res| {
res.map(|(hash, value)| {
let aux_hash = H::hash(&hash);
(self.trie.db().get(&aux_hash, &[]).expect("Missing fatdb hash").into_vec(), value)
})
})
}
}
#[cfg(test)]
mod test {
use memory_db::{MemoryDB, HashKey};
use DBValue;
use keccak_hasher::KeccakHasher;
use reference_trie::{RefFatDBMut, RefFatDB, Trie, TrieMut};
#[test]
fn fatdb_to_trie() {
let mut memdb = MemoryDB::<KeccakHasher, HashKey<_>, DBValue>::default();
let mut root = Default::default();
{
let mut t = RefFatDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
}
let t = RefFatDB::new(&memdb, &root).unwrap();
assert_eq!(t.get(&[0x01u8, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
assert_eq!(
t.iter().unwrap().map(Result::unwrap).collect::<Vec<_>>(),
vec![(vec![0x01u8, 0x23], DBValue::from_slice(&[0x01u8, 0x23] as &[u8]))]);
}
}