1 files changed, 354 insertions, 0 deletions
diff --git a/ethutil/trie.go b/ethutil/trie.go
new file mode 100644
index 000000000..44d2d5774
--- /dev/null
+++ b/ethutil/trie.go
@@ -0,0 +1,354 @@
+package ethutil
+
+import (
+	"fmt"
+	"reflect"
+)
+
+type Node struct {
+	Key   []byte
+	Value *Value
+	Dirty bool
+}
+
+func NewNode(key []byte, val *Value, dirty bool) *Node {
+	return &Node{Key: key, Value: val, Dirty: dirty}
+}
+
+func (n *Node) Copy() *Node {
+	return NewNode(n.Key, n.Value, n.Dirty)
+}
+
+type Cache struct {
+	nodes map[string]*Node
+	db    Database
+}
+
+func NewCache(db Database) *Cache {
+	return &Cache{db: db, nodes: make(map[string]*Node)}
+}
+
+func (cache *Cache) Put(v interface{}) interface{} {
+	value := NewValue(v)
+
+	enc := value.Encode()
+	if len(enc) >= 32 {
+		sha := Sha3Bin(enc)
+
+		cache.nodes[string(sha)] = NewNode(sha, value, true)
+
+		return sha
+	}
+
+	return v
+}
+
+func (cache *Cache) Get(key []byte) *Value {
+	// First check if the key is the cache
+	if cache.nodes[string(key)] != nil {
+		return cache.nodes[string(key)].Value
+	}
+
+	// Get the key of the database instead and cache it
+	data, _ := cache.db.Get(key)
+	// Create the cached value
+	value := NewValueFromBytes(data)
+	// Create caching node
+	cache.nodes[string(key)] = NewNode(key, value, false)
+
+	return value
+}
+
+func (cache *Cache) Commit() {
+	for key, node := range cache.nodes {
+		if node.Dirty {
+			cache.db.Put([]byte(key), node.Value.Encode())
+			node.Dirty = false
+		}
+	}
+
+	// If the nodes grows beyond the 200 entries we simple empty it
+	// FIXME come up with something better
+	if len(cache.nodes) > 200 {
+		cache.nodes = make(map[string]*Node)
+	}
+}
+
+func (cache *Cache) Undo() {
+	for key, node := range cache.nodes {
+		if node.Dirty {
+			delete(cache.nodes, key)
+		}
+	}
+}
+
+// A (modified) Radix Trie implementation
+type Trie struct {
+	Root interface{}
+	//db   Database
+	cache *Cache
+}
+
+func NewTrie(db Database, Root interface{}) *Trie {
+	return &Trie{cache: NewCache(db), Root: Root}
+}
+
+func (t *Trie) Sync() {
+	t.cache.Commit()
+}
+
+/*
+ * Public (query) interface functions
+ */
+func (t *Trie) Update(key string, value string) {
+	k := CompactHexDecode(key)
+
+	t.Root = t.UpdateState(t.Root, k, value)
+}
+
+func (t *Trie) Get(key string) string {
+	k := CompactHexDecode(key)
+	c := NewValue(t.GetState(t.Root, k))
+
+	return c.Str()
+}
+
+func (t *Trie) GetState(node interface{}, key []int) interface{} {
+	n := NewValue(node)
+	// Return the node if key is empty (= found)
+	if len(key) == 0 || n.IsNil() || n.Len() == 0 {
+		return node
+	}
+
+	currentNode := t.GetNode(node)
+	length := currentNode.Len()
+
+	if length == 0 {
+		return ""
+	} else if length == 2 {
+		// Decode the key
+		k := CompactDecode(currentNode.Get(0).Str())
+		v := currentNode.Get(1).Raw()
+
+		if len(key) >= len(k) && CompareIntSlice(k, key[:len(k)]) {
+			return t.GetState(v, key[len(k):])
+		} else {
+			return ""
+		}
+	} else if length == 17 {
+		return t.GetState(currentNode.Get(key[0]).Raw(), key[1:])
+	}
+
+	// It shouldn't come this far
+	fmt.Println("GetState unexpected return")
+	return ""
+}
+
+func (t *Trie) GetNode(node interface{}) *Value {
+	n := NewValue(node)
+
+	if !n.Get(0).IsNil() {
+		return n
+	}
+
+	str := n.Str()
+	if len(str) == 0 {
+		return n
+	} else if len(str) < 32 {
+		return NewValueFromBytes([]byte(str))
+	}
+	/*
+		else {
+			// Fetch the encoded node from the db
+			o, err := t.db.Get(n.Bytes())
+			if err != nil {
+				fmt.Println("Error InsertState", err)
+				return NewValue("")
+			}
+
+			return NewValueFromBytes(o)
+		}
+	*/
+	return t.cache.Get(n.Bytes())
+
+}
+
+func (t *Trie) UpdateState(node interface{}, key []int, value string) interface{} {
+	if value != "" {
+		return t.InsertState(node, key, value)
+	} else {
+		// delete it
+	}
+
+	return ""
+}
+
+func (t *Trie) Put(node interface{}) interface{} {
+	/*
+		enc := Encode(node)
+		if len(enc) >= 32 {
+			var sha []byte
+			sha = Sha3Bin(enc)
+			//t.db.Put([]byte(sha), enc)
+
+			return sha
+		}
+		return node
+	*/
+
+	/*
+		TODO?
+			c := Conv(t.Root)
+			fmt.Println(c.Type(), c.Length())
+			if c.Type() == reflect.String && c.AsString() == "" {
+				return enc
+			}
+	*/
+
+	return t.cache.Put(node)
+
+}
+
+func EmptyStringSlice(l int) []interface{} {
+	slice := make([]interface{}, l)
+	for i := 0; i < l; i++ {
+		slice[i] = ""
+	}
+	return slice
+}
+
+func (t *Trie) InsertState(node interface{}, key []int, value interface{}) interface{} {
+	if len(key) == 0 {
+		return value
+	}
+
+	// New node
+	n := NewValue(node)
+	if node == nil || (n.Type() == reflect.String && (n.Str() == "" || n.Get(0).IsNil())) || n.Len() == 0 {
+		newNode := []interface{}{CompactEncode(key), value}
+
+		return t.Put(newNode)
+	}
+
+	currentNode := t.GetNode(node)
+	// Check for "special" 2 slice type node
+	if currentNode.Len() == 2 {
+		// Decode the key
+		k := CompactDecode(currentNode.Get(0).Str())
+		v := currentNode.Get(1).Raw()
+
+		// Matching key pair (ie. there's already an object with this key)
+		if CompareIntSlice(k, key) {
+			newNode := []interface{}{CompactEncode(key), value}
+			return t.Put(newNode)
+		}
+
+		var newHash interface{}
+		matchingLength := MatchingNibbleLength(key, k)
+		if matchingLength == len(k) {
+			// Insert the hash, creating a new node
+			newHash = t.InsertState(v, key[matchingLength:], value)
+		} else {
+			// Expand the 2 length slice to a 17 length slice
+			oldNode := t.InsertState("", k[matchingLength+1:], v)
+			newNode := t.InsertState("", key[matchingLength+1:], value)
+			// Create an expanded slice
+			scaledSlice := EmptyStringSlice(17)
+			// Set the copied and new node
+			scaledSlice[k[matchingLength]] = oldNode
+			scaledSlice[key[matchingLength]] = newNode
+
+			newHash = t.Put(scaledSlice)
+		}
+
+		if matchingLength == 0 {
+			// End of the chain, return
+			return newHash
+		} else {
+			newNode := []interface{}{CompactEncode(key[:matchingLength]), newHash}
+			return t.Put(newNode)
+		}
+	} else {
+
+		// Copy the current node over to the new node and replace the first nibble in the key
+		newNode := EmptyStringSlice(17)
+
+		for i := 0; i < 17; i++ {
+			cpy := currentNode.Get(i).Raw()
+			if cpy != nil {
+				newNode[i] = cpy
+			}
+		}
+
+		newNode[key[0]] = t.InsertState(currentNode.Get(key[0]).Raw(), key[1:], value)
+
+		return t.Put(newNode)
+	}
+
+	return ""
+}
+
+// Simple compare function which creates a rlp value out of the evaluated objects
+func (t *Trie) Cmp(trie *Trie) bool {
+	return NewValue(t.Root).Cmp(NewValue(trie.Root))
+}
+
+// Returns a copy of this trie
+func (t *Trie) Copy() *Trie {
+	trie := NewTrie(t.cache.db, t.Root)
+	for key, node := range t.cache.nodes {
+		trie.cache.nodes[key] = node.Copy()
+	}
+
+	return trie
+}
+
+/*
+ * Trie helper functions
+ */
+// Helper function for printing out the raw contents of a slice
+func PrintSlice(slice []string) {
+	fmt.Printf("[")
+	for i, val := range slice {
+		fmt.Printf("%q", val)
+		if i != len(slice)-1 {
+			fmt.Printf(",")
+		}
+	}
+	fmt.Printf("]\n")
+}
+
+func PrintSliceT(slice interface{}) {
+	c := Conv(slice)
+	for i := 0; i < c.Length(); i++ {
+		val := c.Get(i)
+		if val.Type() == reflect.Slice {
+			PrintSliceT(val.AsRaw())
+		} else {
+			fmt.Printf("%q", val)
+			if i != c.Length()-1 {
+				fmt.Printf(",")
+			}
+		}
+	}
+}
+
+// RLP Decodes a node in to a [2] or [17] string slice
+func DecodeNode(data []byte) []string {
+	dec, _ := Decode(data, 0)
+	if slice, ok := dec.([]interface{}); ok {
+		strSlice := make([]string, len(slice))
+
+		for i, s := range slice {
+			if str, ok := s.([]byte); ok {
+				strSlice[i] = string(str)
+			}
+		}
+
+		return strSlice
+	} else {
+		fmt.Printf("It wasn't a []. It's a %T\n", dec)
+	}
+
+	return nil
+}