plugeth/ptrie/trie.go
2014-11-18 12:02:13 +01:00

287 lines
5.6 KiB
Go

package ptrie
import (
"bytes"
"sync"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethutil"
"github.com/ethereum/go-ethereum/trie"
)
type Backend interface {
Get([]byte) []byte
Set([]byte, []byte)
}
type Cache map[string][]byte
func (self Cache) Get(key []byte) []byte {
return self[string(key)]
}
func (self Cache) Set(key []byte, data []byte) {
self[string(key)] = data
}
type Trie struct {
mu sync.Mutex
root Node
roothash []byte
backend Backend
}
func NewEmpty() *Trie {
return &Trie{sync.Mutex{}, nil, nil, make(Cache)}
}
func New(root []byte, backend Backend) *Trie {
trie := &Trie{}
trie.roothash = root
trie.backend = backend
value := ethutil.NewValueFromBytes(trie.backend.Get(root))
trie.root = trie.mknode(value)
return trie
}
func (self *Trie) Hash() []byte {
var hash []byte
if self.root != nil {
t := self.root.Hash()
if byts, ok := t.([]byte); ok {
hash = byts
} else {
hash = crypto.Sha3(ethutil.Encode(self.root.RlpData()))
}
} else {
hash = crypto.Sha3(ethutil.Encode(self.root))
}
self.roothash = hash
return hash
}
func (self *Trie) UpdateString(key, value string) Node { return self.Update([]byte(key), []byte(value)) }
func (self *Trie) Update(key, value []byte) Node {
self.mu.Lock()
defer self.mu.Unlock()
k := trie.CompactHexDecode(string(key))
if len(value) != 0 {
self.root = self.insert(self.root, k, &ValueNode{self, value})
} else {
self.root = self.delete(self.root, k)
}
return self.root
}
func (self *Trie) GetString(key string) []byte { return self.Get([]byte(key)) }
func (self *Trie) Get(key []byte) []byte {
self.mu.Lock()
defer self.mu.Unlock()
k := trie.CompactHexDecode(string(key))
n := self.get(self.root, k)
if n != nil {
return n.(*ValueNode).Val()
}
return nil
}
func (self *Trie) DeleteString(key string) Node { return self.Delete([]byte(key)) }
func (self *Trie) Delete(key []byte) Node {
self.mu.Lock()
defer self.mu.Unlock()
k := trie.CompactHexDecode(string(key))
self.root = self.delete(self.root, k)
return self.root
}
func (self *Trie) insert(node Node, key []byte, value Node) Node {
if len(key) == 0 {
return value
}
if node == nil {
return NewShortNode(self, key, value)
}
switch node := node.(type) {
case *ShortNode:
k := node.Key()
cnode := node.Value()
if bytes.Equal(k, key) {
return NewShortNode(self, key, value)
}
var n Node
matchlength := trie.MatchingNibbleLength(key, k)
if matchlength == len(k) {
n = self.insert(cnode, key[matchlength:], value)
} else {
pnode := self.insert(nil, k[matchlength+1:], cnode)
nnode := self.insert(nil, key[matchlength+1:], value)
fulln := NewFullNode(self)
fulln.set(k[matchlength], pnode)
fulln.set(key[matchlength], nnode)
n = fulln
}
if matchlength == 0 {
return n
}
return NewShortNode(self, key[:matchlength], n)
case *FullNode:
cpy := node.Copy().(*FullNode)
cpy.set(key[0], self.insert(node.get(key[0]), key[1:], value))
return cpy
default:
panic("Invalid node")
}
}
func (self *Trie) get(node Node, key []byte) Node {
if len(key) == 0 {
return node
}
if node == nil {
return nil
}
switch node := node.(type) {
case *ShortNode:
k := node.Key()
cnode := node.Value()
if len(key) >= len(k) && bytes.Equal(k, key[:len(k)]) {
return self.get(cnode, key[len(k):])
}
return nil
case *FullNode:
return self.get(node.get(key[0]), key[1:])
default:
panic("Invalid node")
}
}
func (self *Trie) delete(node Node, key []byte) Node {
if len(key) == 0 {
return nil
}
switch node := node.(type) {
case *ShortNode:
k := node.Key()
cnode := node.Value()
if bytes.Equal(key, k) {
return nil
} else if bytes.Equal(key[:len(k)], k) {
child := self.delete(cnode, key[len(k):])
var n Node
switch child := child.(type) {
case *ShortNode:
nkey := append(k, child.Key()...)
n = NewShortNode(self, nkey, child.Value())
case *FullNode:
n = NewShortNode(self, node.key, child)
}
return n
} else {
return node
}
case *FullNode:
n := node.Copy().(*FullNode)
n.set(key[0], self.delete(n.get(key[0]), key[1:]))
pos := -1
for i := 0; i < 17; i++ {
if n.get(byte(i)) != nil {
if pos == -1 {
pos = i
} else {
pos = -2
}
}
}
var nnode Node
if pos == 16 {
nnode = NewShortNode(self, []byte{16}, n.get(byte(pos)))
} else if pos >= 0 {
cnode := n.get(byte(pos))
switch cnode := cnode.(type) {
case *ShortNode:
// Stitch keys
k := append([]byte{byte(pos)}, cnode.Key()...)
nnode = NewShortNode(self, k, cnode.Value())
case *FullNode:
nnode = NewShortNode(self, []byte{byte(pos)}, n.get(byte(pos)))
}
} else {
nnode = n
}
return nnode
default:
panic("Invalid node")
}
}
// casting functions and cache storing
func (self *Trie) mknode(value *ethutil.Value) Node {
l := value.Len()
switch l {
case 2:
return NewShortNode(self, trie.CompactDecode(string(value.Get(0).Bytes())), self.mknode(value.Get(1)))
case 17:
fnode := NewFullNode(self)
for i := 0; i < l; i++ {
fnode.set(byte(i), self.mknode(value.Get(i)))
}
return fnode
case 32:
return &HashNode{value.Bytes()}
default:
return &ValueNode{self, value.Bytes()}
}
}
func (self *Trie) trans(node Node) Node {
switch node := node.(type) {
case *HashNode:
value := ethutil.NewValueFromBytes(self.backend.Get(node.key))
return self.mknode(value)
default:
return node
}
}
func (self *Trie) store(node Node) interface{} {
data := ethutil.Encode(node)
if len(data) >= 32 {
key := crypto.Sha3(data)
self.backend.Set(key, data)
return key
}
return node.RlpData()
}