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use database::DatabaseGuard; use merkle::{MerkleNode, MerkleValue}; use merkle::nibble::{into_key, NibbleVec}; use rlp::{self, Rlp}; use std::ops::Deref; use std::marker::PhantomData; pub struct FixedMerkleIterator<'a, D: DatabaseGuard + 'a, K, V> { iter: MerkleIterator<'a, D>, _marker: PhantomData<(K, V)> } impl<'a, D: DatabaseGuard + 'a, K: rlp::Decodable, V: rlp::Decodable> FixedMerkleIterator<'a, D, K, V> { pub fn new(iter: MerkleIterator<'a, D>) -> Self { FixedMerkleIterator { iter, _marker: PhantomData } } } impl<'a, D: DatabaseGuard + 'a, K: rlp::Decodable, V: rlp::Decodable> Iterator for FixedMerkleIterator<'a, D, K, V> { type Item = (K, V); fn next(&mut self) -> Option<(K, V)> { if let Some((raw_key, raw_value)) = self.iter.next() { let key = rlp::decode(&raw_key); let value = rlp::decode(&raw_value); Some((key, value)) } else { None } } } pub struct MerkleIterator<'a, D: DatabaseGuard + 'a> { database: &'a D, prefix: NibbleVec, value: Vec<u8>, index: usize, child: Option<Box<MerkleIterator<'a, D>>>, is_empty: bool, } impl<'a, D: DatabaseGuard + 'a> MerkleIterator<'a, D> { pub fn new(database: &'a D, value: Vec<u8>) -> Self { Self { database, value, index: 0, child: None, prefix: NibbleVec::new(), is_empty: false, } } pub fn empty(database: &'a D) -> Self { Self { database, value: Vec::new(), index: 0, child: None, prefix: NibbleVec::new(), is_empty: true, } } } fn prepare_value_as_child<'a, D: DatabaseGuard + 'a>( database: &'a D, prefix: NibbleVec, subnibble: NibbleVec, value: MerkleValue ) -> Option<Box<MerkleIterator<'a, D>>> { let mut nibble = prefix.clone(); nibble.extend(subnibble); match value { MerkleValue::Empty => None, MerkleValue::Full(sub_node) => { let value = rlp::encode(sub_node.deref()).to_vec(); Some(Box::new( MerkleIterator { database: database, prefix: nibble, value, index: 0, child: None, is_empty: false, } )) }, MerkleValue::Hash(h) => { let value = database.get(h).unwrap(); Some(Box::new( MerkleIterator { database: database, prefix: nibble, value, index: 0, child: None, is_empty: false, } )) } } } impl<'a, D: DatabaseGuard + 'a> Iterator for MerkleIterator<'a, D> { type Item = (Vec<u8>, Vec<u8>); fn next(&mut self) -> Option<(Vec<u8>, Vec<u8>)> { if self.is_empty { return None; } let node = MerkleNode::decode(&Rlp::new(&self.value)); match node { MerkleNode::Leaf(node_nibble, node_value) => { debug_assert!(self.child.is_none()); if self.index == 0 { self.index += 1; let mut nibble = self.prefix.clone(); nibble.extend(node_nibble); Some((into_key(&nibble), node_value.into())) } else { None } }, MerkleNode::Extension(node_nibble, node_value) => { if self.index == 0 { debug_assert!(self.child.is_none()); self.child = prepare_value_as_child( self.database, self.prefix.clone(), node_nibble, node_value); if self.child.is_some() { self.index += 1; self.child.as_mut().unwrap().next() } else { None } } else { debug_assert!(self.child.is_some()); self.child.as_mut().unwrap().next() } }, MerkleNode::Branch(nodes, additional) => { debug_assert!(self.index <= 17); while self.index <= 16 { if self.index < 16 { if self.child.is_some() { match self.child.as_mut().unwrap().next() { Some(val) => return Some(val), None => { self.child = None; }, } } else { let value = nodes[self.index].clone(); let subnibble = vec![self.index.into()]; self.index += 1; self.child = prepare_value_as_child( self.database, self.prefix.clone(), subnibble, value); } } else { self.index += 1; match additional { Some(val) => return Some((into_key(&self.prefix), val.into())), None => (), } } } None }, } } }