1 files changed, 154 insertions, 0 deletions
diff --git a/core/state/iterator.go b/core/state/iterator.go
new file mode 100644
index 0000000..c6d2a48
--- /dev/null
+++ b/core/state/iterator.go
@@ -0,0 +1,154 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/rlp"
+	"github.com/ava-labs/go-ethereum/trie"
+)
+
+// NodeIterator is an iterator to traverse the entire state trie post-order,
+// including all of the contract code and contract state tries.
+type NodeIterator struct {
+	state *StateDB // State being iterated
+
+	stateIt trie.NodeIterator // Primary iterator for the global state trie
+	dataIt  trie.NodeIterator // Secondary iterator for the data trie of a contract
+
+	accountHash common.Hash // Hash of the node containing the account
+	codeHash    common.Hash // Hash of the contract source code
+	code        []byte      // Source code associated with a contract
+
+	Hash   common.Hash // Hash of the current entry being iterated (nil if not standalone)
+	Parent common.Hash // Hash of the first full ancestor node (nil if current is the root)
+
+	Error error // Failure set in case of an internal error in the iterator
+}
+
+// NewNodeIterator creates an post-order state node iterator.
+func NewNodeIterator(state *StateDB) *NodeIterator {
+	return &NodeIterator{
+		state: state,
+	}
+}
+
+// Next moves the iterator to the next node, returning whether there are any
+// further nodes. In case of an internal error this method returns false and
+// sets the Error field to the encountered failure.
+func (it *NodeIterator) Next() bool {
+	// If the iterator failed previously, don't do anything
+	if it.Error != nil {
+		return false
+	}
+	// Otherwise step forward with the iterator and report any errors
+	if err := it.step(); err != nil {
+		it.Error = err
+		return false
+	}
+	return it.retrieve()
+}
+
+// step moves the iterator to the next entry of the state trie.
+func (it *NodeIterator) step() error {
+	// Abort if we reached the end of the iteration
+	if it.state == nil {
+		return nil
+	}
+	// Initialize the iterator if we've just started
+	if it.stateIt == nil {
+		it.stateIt = it.state.trie.NodeIterator(nil)
+	}
+	// If we had data nodes previously, we surely have at least state nodes
+	if it.dataIt != nil {
+		if cont := it.dataIt.Next(true); !cont {
+			if it.dataIt.Error() != nil {
+				return it.dataIt.Error()
+			}
+			it.dataIt = nil
+		}
+		return nil
+	}
+	// If we had source code previously, discard that
+	if it.code != nil {
+		it.code = nil
+		return nil
+	}
+	// Step to the next state trie node, terminating if we're out of nodes
+	if cont := it.stateIt.Next(true); !cont {
+		if it.stateIt.Error() != nil {
+			return it.stateIt.Error()
+		}
+		it.state, it.stateIt = nil, nil
+		return nil
+	}
+	// If the state trie node is an internal entry, leave as is
+	if !it.stateIt.Leaf() {
+		return nil
+	}
+	// Otherwise we've reached an account node, initiate data iteration
+	var account Account
+	if err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob()), &account); err != nil {
+		return err
+	}
+	dataTrie, err := it.state.db.OpenStorageTrie(common.BytesToHash(it.stateIt.LeafKey()), account.Root)
+	if err != nil {
+		return err
+	}
+	it.dataIt = dataTrie.NodeIterator(nil)
+	if !it.dataIt.Next(true) {
+		it.dataIt = nil
+	}
+	if !bytes.Equal(account.CodeHash, emptyCodeHash) {
+		it.codeHash = common.BytesToHash(account.CodeHash)
+		addrHash := common.BytesToHash(it.stateIt.LeafKey())
+		it.code, err = it.state.db.ContractCode(addrHash, common.BytesToHash(account.CodeHash))
+		if err != nil {
+			return fmt.Errorf("code %x: %v", account.CodeHash, err)
+		}
+	}
+	it.accountHash = it.stateIt.Parent()
+	return nil
+}
+
+// retrieve pulls and caches the current state entry the iterator is traversing.
+// The method returns whether there are any more data left for inspection.
+func (it *NodeIterator) retrieve() bool {
+	// Clear out any previously set values
+	it.Hash = common.Hash{}
+
+	// If the iteration's done, return no available data
+	if it.state == nil {
+		return false
+	}
+	// Otherwise retrieve the current entry
+	switch {
+	case it.dataIt != nil:
+		it.Hash, it.Parent = it.dataIt.Hash(), it.dataIt.Parent()
+		if it.Parent == (common.Hash{}) {
+			it.Parent = it.accountHash
+		}
+	case it.code != nil:
+		it.Hash, it.Parent = it.codeHash, it.accountHash
+	case it.stateIt != nil:
+		it.Hash, it.Parent = it.stateIt.Hash(), it.stateIt.Parent()
+	}
+	return true
+}