make triedbmut lookup shorter

This commit is contained in:
debris 2017-08-29 12:31:40 +02:00
parent e390e6b0af
commit 100d1c7bf6

View File

@ -370,64 +370,49 @@ impl<'a> TrieDBMut<'a> {
fn lookup<'x, 'key>(&'x self, mut partial: NibbleSlice<'key>, handle: &NodeHandle) -> super::Result<Option<DBValue>> fn lookup<'x, 'key>(&'x self, mut partial: NibbleSlice<'key>, handle: &NodeHandle) -> super::Result<Option<DBValue>>
where 'x: 'key where 'x: 'key
{ {
enum Step<'s> {
Return(Option<DBValue>),
Lookup(usize, &'s NodeHandle),
}
let mut handle = handle; let mut handle = handle;
loop { loop {
let step = { let (mid, child) = match *handle {
match *handle { NodeHandle::Hash(ref hash) => return Lookup {
NodeHandle::Hash(ref hash) => {
let lookup = Lookup {
db: &*self.db, db: &*self.db,
query: DBValue::from_slice, query: DBValue::from_slice,
hash: hash.clone(), hash: hash.clone(),
}.look_up(partial)?; }.look_up(partial),
Step::Return(lookup)
},
NodeHandle::InMemory(ref handle) => match self.storage[handle] { NodeHandle::InMemory(ref handle) => match self.storage[handle] {
Node::Empty => Step::Return(None), Node::Empty => return Ok(None),
Node::Leaf(ref key, ref value) => { Node::Leaf(ref key, ref value) => {
if NibbleSlice::from_encoded(key).0 == partial { if NibbleSlice::from_encoded(key).0 == partial {
Step::Return(Some(DBValue::from_slice(value))) return Ok(Some(DBValue::from_slice(value)));
} else { } else {
Step::Return(None) return Ok(None);
} }
} }
Node::Extension(ref slice, ref child) => { Node::Extension(ref slice, ref child) => {
let slice = NibbleSlice::from_encoded(slice).0; let slice = NibbleSlice::from_encoded(slice).0;
if partial.starts_with(&slice) { if partial.starts_with(&slice) {
Step::Lookup(slice.len(), child) (slice.len(), child)
} else { } else {
Step::Return(None) return Ok(None);
} }
} }
Node::Branch(ref children, ref value) => { Node::Branch(ref children, ref value) => {
if partial.is_empty() { if partial.is_empty() {
Step::Return(value.as_ref().map(|v| DBValue::from_slice(v))) return Ok(value.as_ref().map(|v| DBValue::from_slice(v)));
} else { } else {
let idx = partial.at(0); let idx = partial.at(0);
match children[idx as usize].as_ref() { match children[idx as usize].as_ref() {
Some(child) => Step::Lookup(1, child), Some(child) => (1, child),
None => Step::Return(None), None => return Ok(None),
}
} }
} }
} }
} }
}; };
match step {
Step::Return(r) => return Ok(r),
Step::Lookup(mid, child) => {
partial = partial.mid(mid); partial = partial.mid(mid);
handle = child; handle = child;
} }
} }
}
}
/// insert a key, value pair into the trie, creating new nodes if necessary. /// 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>) fn insert_at(&mut self, handle: NodeHandle, partial: NibbleSlice, value: DBValue, old_val: &mut Option<DBValue>)