From 2fb08643cbd862a07801de09aa0aa55edc583bfa Mon Sep 17 00:00:00 2001
From: Nick Johnson <arachnid@notdot.net>
Date: Mon, 24 Oct 2016 11:58:50 +0100
Subject: [PATCH] Remove NodeIterator from the storage interface

---
 core/state/iterator.go     |  4 ++--
 core/state/state_object.go |  2 +-
 core/state/statedb.go      |  8 +++----
 trie/directcache.go        |  4 ----
 trie/iterator.go           |  8 +++----
 trie/proof.go              |  2 +-
 trie/proof_test.go         |  2 +-
 trie/secure_trie_test.go   |  2 +-
 trie/sync_test.go          |  4 ++--
 trie/trie.go               | 49 +++++++++++++++++---------------------
 trie/trie_test.go          |  8 +++----
 11 files changed, 42 insertions(+), 51 deletions(-)

diff --git a/core/state/iterator.go b/core/state/iterator.go
index f48aab5583..9600c92ed5 100644
--- a/core/state/iterator.go
+++ b/core/state/iterator.go
@@ -76,7 +76,7 @@ func (it *NodeIterator) step() error {
 	}
 	// Initialize the iterator if we've just started
 	if it.stateIt == nil {
-		it.stateIt = it.state.trie.NodeIterator()
+		it.stateIt = trie.NewNodeIterator(it.state.trie)
 	}
 	// If we had data nodes previously, we surely have at least state nodes
 	if it.dataIt != nil {
@@ -119,7 +119,7 @@ func (it *NodeIterator) step() error {
 	if err != nil {
 		return err
 	}
-	it.dataIt = dataTrie.NodeIterator()
+	it.dataIt = trie.NewNodeIterator(dataTrie)
 	if !it.dataIt.Next() {
 		it.dataIt = nil
 	}
diff --git a/core/state/state_object.go b/core/state/state_object.go
index 1817299493..cd60c33776 100644
--- a/core/state/state_object.go
+++ b/core/state/state_object.go
@@ -76,7 +76,7 @@ type StateObject struct {
 	dbErr error
 
 	// Write caches.
-	trie *trie.SimpleTrie // storage trie, which becomes non-nil on first access
+	trie *trie.Trie // storage trie, which becomes non-nil on first access
 	storage *trie.SecureTrie // Interface to storage
 	code Code             // contract bytecode, which gets set when code is loaded
 
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 2fd41e6180..eef2f38d50 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -62,9 +62,9 @@ type revision struct {
 // * Accounts
 type StateDB struct {
 	db            ethdb.Database
-	trie          *trie.SimpleTrie
+	trie          *trie.Trie
 	storage       *trie.SecureTrie
-	pastTries     []*trie.SimpleTrie
+	pastTries     []*trie.Trie
 	codeSizeCache *lru.Cache
 
 	// This map holds 'live' objects, which will get modified while processing a state transition.
@@ -155,7 +155,7 @@ func (self *StateDB) Reset(root common.Hash) error {
 
 // openTrie creates a trie. It uses an existing trie if one is available
 // from the journal if available.
-func (self *StateDB) openTrie(root common.Hash) (*trie.SimpleTrie, error) {
+func (self *StateDB) openTrie(root common.Hash) (*trie.Trie, error) {
 	for i := len(self.pastTries) - 1; i >= 0; i-- {
 		if self.pastTries[i].Hash() == root {
 			tr := *self.pastTries[i]
@@ -165,7 +165,7 @@ func (self *StateDB) openTrie(root common.Hash) (*trie.SimpleTrie, error) {
 	return trie.New(root, self.db, MaxTrieCacheGen)
 }
 
-func (self *StateDB) pushTrie(t *trie.SimpleTrie) {
+func (self *StateDB) pushTrie(t *trie.Trie) {
 	self.lock.Lock()
 	defer self.lock.Unlock()
 
diff --git a/trie/directcache.go b/trie/directcache.go
index 0d2a0f2410..6f87ba5ef8 100644
--- a/trie/directcache.go
+++ b/trie/directcache.go
@@ -70,10 +70,6 @@ func (dc *DirectCache) Iterator() *Iterator {
 	return dc.storage.Iterator()
 }
 
-func (dc *DirectCache) NodeIterator() *NodeIterator {
-	return dc.storage.NodeIterator()
-}
-
 func (dc *DirectCache) makeKey(key []byte) []byte {
 	return append(dc.keyPrefix, key...)
 }
diff --git a/trie/iterator.go b/trie/iterator.go
index 750bbab12c..4b5f42890a 100644
--- a/trie/iterator.go
+++ b/trie/iterator.go
@@ -20,7 +20,7 @@ import "github.com/ethereum/go-ethereum/common"
 
 // Iterator is a key-value trie iterator that traverses a Trie.
 type Iterator struct {
-	trie   *SimpleTrie
+	trie   *Trie
 	nodeIt *NodeIterator
 	keyBuf []byte
 
@@ -29,7 +29,7 @@ type Iterator struct {
 }
 
 // NewIterator creates a new key-value iterator.
-func NewIterator(trie *SimpleTrie) *Iterator {
+func NewIterator(trie *Trie) *Iterator {
 	return &Iterator{
 		trie:   trie,
 		nodeIt: NewNodeIterator(trie),
@@ -82,7 +82,7 @@ type nodeIteratorState struct {
 
 // NodeIterator is an iterator to traverse the trie post-order.
 type NodeIterator struct {
-	trie  *SimpleTrie          // Trie being iterated
+	trie  *Trie          // Trie being iterated
 	stack []*nodeIteratorState // Hierarchy of trie nodes persisting the iteration state
 
 	Hash     common.Hash // Hash of the current node being iterated (nil if not standalone)
@@ -95,7 +95,7 @@ type NodeIterator struct {
 }
 
 // NewNodeIterator creates an post-order trie iterator.
-func NewNodeIterator(trie *SimpleTrie) *NodeIterator {
+func NewNodeIterator(trie *Trie) *NodeIterator {
 	if trie.Hash() == emptyState {
 		return new(NodeIterator)
 	}
diff --git a/trie/proof.go b/trie/proof.go
index bf796a95cd..bea5e5c098 100644
--- a/trie/proof.go
+++ b/trie/proof.go
@@ -37,7 +37,7 @@ import (
 // contains all nodes of the longest existing prefix of the key
 // (at least the root node), ending with the node that proves the
 // absence of the key.
-func (t *SimpleTrie) Prove(key []byte) []rlp.RawValue {
+func (t *Trie) Prove(key []byte) []rlp.RawValue {
 	// Collect all nodes on the path to key.
 	key = compactHexDecode(key)
 	nodes := []node{}
diff --git a/trie/proof_test.go b/trie/proof_test.go
index eddbafe00a..ce7eac5045 100644
--- a/trie/proof_test.go
+++ b/trie/proof_test.go
@@ -129,7 +129,7 @@ func BenchmarkVerifyProof(b *testing.B) {
 	}
 }
 
-func randomTrie(n int) (*SimpleTrie, map[string]*kv) {
+func randomTrie(n int) (*Trie, map[string]*kv) {
 	trie, _ := New(common.Hash{}, nil, 0)
 	vals := make(map[string]*kv)
 	for i := byte(0); i < 100; i++ {
diff --git a/trie/secure_trie_test.go b/trie/secure_trie_test.go
index a595c2f1ea..7b8907deeb 100644
--- a/trie/secure_trie_test.go
+++ b/trie/secure_trie_test.go
@@ -27,7 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/ethdb"
 )
 
-func newEmptySecure() (*SimpleTrie, *SecureTrie) {
+func newEmptySecure() (*Trie, *SecureTrie) {
 	db, _ := ethdb.NewMemDatabase()
 	tr, _ := New(common.Hash{}, db, 0)
 	st := NewSecure(tr, db)
diff --git a/trie/sync_test.go b/trie/sync_test.go
index 62db45a01d..a28e81adb7 100644
--- a/trie/sync_test.go
+++ b/trie/sync_test.go
@@ -25,7 +25,7 @@ import (
 )
 
 // makeTestTrie create a sample test trie to test node-wise reconstruction.
-func makeTestTrie() (ethdb.Database, *SimpleTrie, map[string][]byte) {
+func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
 	// Create an empty trie
 	db, _ := ethdb.NewMemDatabase()
 	trie, _ := New(common.Hash{}, db, 0)
@@ -91,7 +91,7 @@ func TestEmptyTrieSync(t *testing.T) {
 	emptyA, _ := New(common.Hash{}, nil, 0)
 	emptyB, _ := New(emptyRoot, nil, 0)
 
-	for i, trie := range []*SimpleTrie{emptyA, emptyB} {
+	for i, trie := range []*Trie{emptyA, emptyB} {
 		db, _ := ethdb.NewMemDatabase()
 		if req := NewTrieSync(common.BytesToHash(trie.Root()), db, nil).Missing(1); len(req) != 0 {
 			t.Errorf("test %d: content requested for empty trie: %v", i, req)
diff --git a/trie/trie.go b/trie/trie.go
index f9eae6053e..e186fc1d7c 100644
--- a/trie/trie.go
+++ b/trie/trie.go
@@ -80,7 +80,6 @@ type DatabaseWriter interface {
 // trie is not safe for concurrent use.
 type Storage interface {
 	Iterator() *Iterator
-	NodeIterator() *NodeIterator
 	Get(key []byte) []byte
 	TryGet(key []byte) ([]byte, error)
 	Update(key, value []byte)
@@ -91,7 +90,7 @@ type Storage interface {
 	CommitTo(db DatabaseWriter) (root common.Hash, err error)
 }
 
-type SimpleTrie struct {
+type Trie struct {
 	root         node
 	db           Database
 	originalRoot common.Hash
@@ -104,7 +103,7 @@ type SimpleTrie struct {
 }
 
 // newFlag returns the cache flag value for a newly created node.
-func (t *SimpleTrie) newFlag() nodeFlag {
+func (t *Trie) newFlag() nodeFlag {
 	return nodeFlag{dirty: true, gen: t.cachegen}
 }
 
@@ -117,11 +116,11 @@ func (t *SimpleTrie) newFlag() nodeFlag {
 //
 // cacheLimit is the number of 'cache generations' to keep.
 // A cache generations is created by a call to Commit.
-func New(root common.Hash, db Database, cacheLimit uint16) (*SimpleTrie, error) {
-	trie := &SimpleTrie{db: db, originalRoot: root, cachelimit: cacheLimit}
+func New(root common.Hash, db Database, cacheLimit uint16) (*Trie, error) {
+	trie := &Trie{db: db, originalRoot: root, cachelimit: cacheLimit}
 	if (root != common.Hash{}) && root != emptyRoot {
 		if db == nil {
-			panic("SimpleTrie.New: cannot use existing root without a database")
+			panic("Trie.New: cannot use existing root without a database")
 		}
 		rootnode, err := trie.resolveHash(root[:], nil, nil)
 		if err != nil {
@@ -133,17 +132,13 @@ func New(root common.Hash, db Database, cacheLimit uint16) (*SimpleTrie, error)
 }
 
 // Iterator returns an iterator over all mappings in the trie.
-func (t *SimpleTrie) Iterator() *Iterator {
+func (t *Trie) Iterator() *Iterator {
 	return NewIterator(t)
 }
 
-func (t *SimpleTrie) NodeIterator() *NodeIterator {
-	return NewNodeIterator(t)
-}
-
 // Get returns the value for key stored in the trie.
 // The value bytes must not be modified by the caller.
-func (t *SimpleTrie) Get(key []byte) []byte {
+func (t *Trie) Get(key []byte) []byte {
 	res, err := t.TryGet(key)
 	if err != nil && glog.V(logger.Error) {
 		glog.Errorf("Unhandled trie error: %v", err)
@@ -154,7 +149,7 @@ func (t *SimpleTrie) Get(key []byte) []byte {
 // TryGet returns the value for key stored in the trie.
 // The value bytes must not be modified by the caller.
 // If a node was not found in the database, a MissingNodeError is returned.
-func (t *SimpleTrie) TryGet(key []byte) ([]byte, error) {
+func (t *Trie) TryGet(key []byte) ([]byte, error) {
 	key = compactHexDecode(key)
 	value, newroot, didResolve, err := t.tryGet(t.root, key, 0)
 	if err == nil && didResolve {
@@ -163,7 +158,7 @@ func (t *SimpleTrie) TryGet(key []byte) ([]byte, error) {
 	return value, err
 }
 
-func (t *SimpleTrie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode node, didResolve bool, err error) {
+func (t *Trie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode node, didResolve bool, err error) {
 	switch n := (origNode).(type) {
 	case nil:
 		return nil, nil, false, nil
@@ -207,7 +202,7 @@ func (t *SimpleTrie) tryGet(origNode node, key []byte, pos int) (value []byte, n
 //
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
-func (t *SimpleTrie) Update(key, value []byte) {
+func (t *Trie) Update(key, value []byte) {
 	if err := t.TryUpdate(key, value); err != nil && glog.V(logger.Error) {
 		glog.Errorf("Unhandled trie error: %v", err)
 	}
@@ -221,7 +216,7 @@ func (t *SimpleTrie) Update(key, value []byte) {
 // stored in the trie.
 //
 // If a node was not found in the database, a MissingNodeError is returned.
-func (t *SimpleTrie) TryUpdate(key, value []byte) error {
+func (t *Trie) TryUpdate(key, value []byte) error {
 	k := compactHexDecode(key)
 	if len(value) != 0 {
 		_, n, err := t.insert(t.root, nil, k, valueNode(value))
@@ -239,7 +234,7 @@ func (t *SimpleTrie) TryUpdate(key, value []byte) error {
 	return nil
 }
 
-func (t *SimpleTrie) insert(n node, prefix, key []byte, value node) (bool, node, error) {
+func (t *Trie) insert(n node, prefix, key []byte, value node) (bool, node, error) {
 	if len(key) == 0 {
 		if v, ok := n.(valueNode); ok {
 			return !bytes.Equal(v, value.(valueNode)), value, nil
@@ -309,7 +304,7 @@ func (t *SimpleTrie) insert(n node, prefix, key []byte, value node) (bool, node,
 }
 
 // Delete removes any existing value for key from the trie.
-func (t *SimpleTrie) Delete(key []byte) {
+func (t *Trie) Delete(key []byte) {
 	if err := t.TryDelete(key); err != nil && glog.V(logger.Error) {
 		glog.Errorf("Unhandled trie error: %v", err)
 	}
@@ -317,7 +312,7 @@ func (t *SimpleTrie) Delete(key []byte) {
 
 // TryDelete removes any existing value for key from the trie.
 // If a node was not found in the database, a MissingNodeError is returned.
-func (t *SimpleTrie) TryDelete(key []byte) error {
+func (t *Trie) TryDelete(key []byte) error {
 	k := compactHexDecode(key)
 	_, n, err := t.delete(t.root, nil, k)
 	if err != nil {
@@ -330,7 +325,7 @@ func (t *SimpleTrie) TryDelete(key []byte) error {
 // delete returns the new root of the trie with key deleted.
 // It reduces the trie to minimal form by simplifying
 // nodes on the way up after deleting recursively.
-func (t *SimpleTrie) delete(n node, prefix, key []byte) (bool, node, error) {
+func (t *Trie) delete(n node, prefix, key []byte) (bool, node, error) {
 	switch n := n.(type) {
 	case *shortNode:
 		matchlen := prefixLen(key, n.Key)
@@ -446,14 +441,14 @@ func concat(s1 []byte, s2 ...byte) []byte {
 	return r
 }
 
-func (t *SimpleTrie) resolve(n node, prefix, suffix []byte) (node, error) {
+func (t *Trie) resolve(n node, prefix, suffix []byte) (node, error) {
 	if n, ok := n.(hashNode); ok {
 		return t.resolveHash(n, prefix, suffix)
 	}
 	return n, nil
 }
 
-func (t *SimpleTrie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
+func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
 	cacheMissCounter.Inc(1)
 
 	enc, err := t.db.Get(n)
@@ -472,11 +467,11 @@ func (t *SimpleTrie) resolveHash(n hashNode, prefix, suffix []byte) (node, error
 
 // Root returns the root hash of the trie.
 // Deprecated: use Hash instead.
-func (t *SimpleTrie) Root() []byte { return t.Hash().Bytes() }
+func (t *Trie) Root() []byte { return t.Hash().Bytes() }
 
 // Hash returns the root hash of the trie. It does not write to the
 // database and can be used even if the trie doesn't have one.
-func (t *SimpleTrie) Hash() common.Hash {
+func (t *Trie) Hash() common.Hash {
 	hash, cached, _ := t.hashRoot(nil)
 	t.root = cached
 	return common.BytesToHash(hash.(hashNode))
@@ -487,7 +482,7 @@ func (t *SimpleTrie) Hash() common.Hash {
 //
 // Committing flushes nodes from memory.
 // Subsequent Get calls will load nodes from the database.
-func (t *SimpleTrie) Commit() (root common.Hash, err error) {
+func (t *Trie) Commit() (root common.Hash, err error) {
 	if t.db == nil {
 		panic("Commit called on trie with nil database")
 	}
@@ -501,7 +496,7 @@ func (t *SimpleTrie) Commit() (root common.Hash, err error) {
 // load nodes from the trie's database. Calling code must ensure that
 // the changes made to db are written back to the trie's attached
 // database before using the trie.
-func (t *SimpleTrie) CommitTo(db DatabaseWriter) (root common.Hash, err error) {
+func (t *Trie) CommitTo(db DatabaseWriter) (root common.Hash, err error) {
 	hash, cached, err := t.hashRoot(db)
 	if err != nil {
 		return (common.Hash{}), err
@@ -511,7 +506,7 @@ func (t *SimpleTrie) CommitTo(db DatabaseWriter) (root common.Hash, err error) {
 	return common.BytesToHash(hash.(hashNode)), nil
 }
 
-func (t *SimpleTrie) hashRoot(db DatabaseWriter) (node, node, error) {
+func (t *Trie) hashRoot(db DatabaseWriter) (node, node, error) {
 	if t.root == nil {
 		return hashNode(emptyRoot.Bytes()), nil, nil
 	}
diff --git a/trie/trie_test.go b/trie/trie_test.go
index fd641d8e10..bb2861cf19 100644
--- a/trie/trie_test.go
+++ b/trie/trie_test.go
@@ -38,14 +38,14 @@ func init() {
 }
 
 // Used for testing
-func newEmpty() *SimpleTrie {
+func newEmpty() *Trie {
 	db, _ := ethdb.NewMemDatabase()
 	trie, _ := New(common.Hash{}, db, 0)
 	return trie
 }
 
 func TestEmptyTrie(t *testing.T) {
-	var trie SimpleTrie
+	var trie Trie
 	res := trie.Hash()
 	exp := emptyRoot
 	if res != common.Hash(exp) {
@@ -54,7 +54,7 @@ func TestEmptyTrie(t *testing.T) {
 }
 
 func TestNull(t *testing.T) {
-	var trie SimpleTrie
+	var trie Trie
 	key := make([]byte, 32)
 	value := common.FromHex("0x823140710bf13990e4500136726d8b55")
 	trie.Update(key, value)
@@ -547,7 +547,7 @@ func benchGet(b *testing.B, commit bool) {
 	}
 }
 
-func benchUpdate(b *testing.B, e binary.ByteOrder) *SimpleTrie {
+func benchUpdate(b *testing.B, e binary.ByteOrder) *Trie {
 	trie := newEmpty()
 	k := make([]byte, 32)
 	for i := 0; i < b.N; i++ {