Merge a2b4d989ca into 0ab8a175d8

core/chain_makers.go

@@ -185,11 +185,15 @@ func GenerateChain(parent *types.Block, db ethdb.Database, n int, gen func(int,
 			panic(fmt.Sprintf("state write error: %v", err))
 		}
 		h.Root = root
+		for _, receipt := range b.receipts {
+			fmt.Printf("%+v\n", receipt)
+		}
 		return types.NewBlock(h, b.txs, b.uncles, b.receipts), b.receipts
 	}
 	for i := 0; i < n; i++ {
 		header := makeHeader(parent, statedb)
 		block, receipt := genblock(i, header)
+		fmt.Printf("%x\n\n", block.Header().ReceiptHash)
 		blocks[i] = block
 		receipts[i] = receipt
 		parent = block

core/index_test.go

@@ -0,0 +1,160 @@
+// 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 core
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// blackHoleContract is a trivial Ethereum contract that can just store some data
+// points in its state trie. It's goal is to have a means to test functionality
+// depending on evolving state roots.
+//
+// contract BlackHole {
+//     mapping (int256 => uint) public data;
+//
+//     function set(int256 key, uint value) {
+//         data[key] = value;
+//     }
+// }
+var blackHoleContract = common.Hex2Bytes("6060604052605f8060106000396000f3606060405260e060020a60003504639398e0cd81146024578063a22c554014603b575b005b605560043560006020819052908152604090205481565b600435600090815260208190526040902060243590556022565b6060908152602090f3")
+var blackHoleSetter = common.Hex2Bytes("a22c5540")
+
+// Tests that state trie indexes are properly constructed for an entire chain of
+// imported blocks, cross referencing between various state roots, as well as
+// making sure that state updates do not lose reference entries.
+func TestChainIndex(t *testing.T) {
+	// Configure the test chain and ensure we have enough funds to play with
+	var (
+		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
+		key3, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
+		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
+		addr2   = crypto.PubkeyToAddress(key2.PublicKey)
+		addr3   = crypto.PubkeyToAddress(key3.PublicKey)
+		db, _   = ethdb.NewMemDatabase()
+	)
+	genesis := WriteGenesisBlockForTesting(db, GenesisAccount{addr1, big.NewInt(10000000000)})
+
+	// Generate a chain will all kinds of events happening in it
+	var contract common.Address
+
+	chain, _ := GenerateChain(genesis, db, 8, func(i int, gen *BlockGen) {
+		switch i {
+		case 0:
+			// In block 1, addr1 sends addr2 some ether.
+			tx, _ := types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil).SignECDSA(key1)
+			gen.AddTx(tx)
+		case 1:
+			// In block 2, addr1 sends some more ether to addr2.
+			// addr2 passes it on to addr3.
+			tx1, _ := types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(key1)
+			tx2, _ := types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(key2)
+			gen.AddTx(tx1)
+			gen.AddTx(tx2)
+		case 2:
+			// Block 3 is empty but was mined by addr3.
+			gen.SetCoinbase(addr3)
+			gen.SetExtra([]byte("yeehaw"))
+		case 3:
+			// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
+			b2 := gen.PrevBlock(1).Header()
+			b2.Extra = []byte("foo")
+			gen.AddUncle(b2)
+			b3 := gen.PrevBlock(2).Header()
+			b3.Extra = []byte("foo")
+			gen.AddUncle(b3)
+		case 4:
+			// In block 5, we create a simple storage contract to add data entries to
+			tx, _ := types.NewContractCreation(gen.TxNonce(addr1), big.NewInt(31415), params.GenesisGasLimit, big.NewInt(1), blackHoleContract).SignECDSA(key1)
+			contract = crypto.CreateAddress(addr1, tx.Nonce())
+			gen.AddTx(tx)
+		case 5:
+			// In block 6, we store a single entry into the storage to check single update indexing
+			key := common.Hex2BytesFixed("01", 32)
+			val := common.Hex2BytesFixed("02", 32)
+
+			tx, _ := types.NewTransaction(gen.TxNonce(addr1), contract, nil, params.GenesisGasLimit, nil, append(append(blackHoleSetter, key...), val...)).SignECDSA(key1)
+			gen.AddTx(tx)
+		case 6:
+			// In block 7, we store a lot of entries into the storage to check multi update indexing
+			for i := int64(0); i < 50; i++ {
+				key := common.Hex2BytesFixed(common.Bytes2Hex(big.NewInt(i).Bytes()), 32)
+				val := common.Hex2BytesFixed(common.Bytes2Hex(big.NewInt(i+2).Bytes()), 32)
+
+				tx, _ := types.NewTransaction(gen.TxNonce(addr1), contract, nil, big.NewInt(45000), nil, append(append(blackHoleSetter, key...), val...)).SignECDSA(key1)
+				gen.AddTx(tx)
+			}
+		}
+	})
+	// Import the chain. This runs all block validation rules.
+	evmux := &event.TypeMux{}
+
+	vm.Debug = true
+
+	blockchain, _ := NewBlockChain(db, FakePow{}, evmux)
+	if i, err := blockchain.InsertChain(chain); err != nil {
+		t.Fatalf("block %d: insert failed: %v\n", i, err)
+		return
+	}
+	// Iterate over all the blocks and check the state trie indexes
+	indexes := make(map[string]struct{})
+
+	for block := uint64(0); block <= blockchain.CurrentBlock().NumberU64(); block++ {
+		// Gather all the indexes that should be present in the database
+		root := blockchain.GetBlockByNumber(block).Root()
+
+		stateDb, err := state.New(root, db)
+		if err != nil {
+			t.Fatalf("failed to create state trie at %x: %v", root, err)
+		}
+		fmt.Println(blockchain.GetBlockByNumber(block).Transactions())
+		for it := state.NewNodeIterator(stateDb); it.Next(); {
+			if (it.Hash != common.Hash{}) && (it.Parent != common.Hash{}) {
+				fmt.Printf("%d: %x -> %x\n", block, it.Parent, it.Hash)
+				indexes[string(trie.ParentReferenceIndexKey(it.Parent.Bytes(), it.Hash.Bytes()))] = struct{}{}
+			}
+		}
+	}
+	// Cross check the indexes and the database itself
+	fmt.Println(len(indexes))
+	for index, _ := range indexes {
+		if _, err := db.Get([]byte(index)); err != nil {
+			t.Errorf("failed to retrieve reported index %x: %v", index, err)
+		}
+	}
+	for _, key := range db.Keys() {
+		if bytes.HasPrefix(key, trie.ParentReferenceIndexPrefix) {
+			if _, ok := indexes[string(key)]; !ok {
+				t.Errorf("index entry not reported %x", key)
+			}
+		}
+	}
+}

core/state/index_test.go

@@ -0,0 +1,57 @@
+// 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"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// Tests that all index entries are stored in the database after a state commit.
+func TestStateIndex(t *testing.T) {
+	// Create some arbitrary test state to iterate
+	db, root, _ := makeTestState()
+
+	state, err := New(root, db)
+	if err != nil {
+		t.Fatalf("failed to create state trie at %x: %v", root, err)
+	}
+	// Gather all the indexes that should be present in the database
+	indexes := make(map[string]struct{})
+	for it := NewNodeIterator(state); it.Next(); {
+		if (it.Hash != common.Hash{}) && (it.Parent != common.Hash{}) {
+			indexes[string(trie.ParentReferenceIndexKey(it.Parent.Bytes(), it.Hash.Bytes()))] = struct{}{}
+		}
+	}
+	// Cross check the indexes and the database itself
+	for index, _ := range indexes {
+		if _, err := db.Get([]byte(index)); err != nil {
+			t.Errorf("failed to retrieve reported index %x: %v", index, err)
+		}
+	}
+	for _, key := range db.(*ethdb.MemDatabase).Keys() {
+		if bytes.HasPrefix(key, trie.ParentReferenceIndexPrefix) {
+			if _, ok := indexes[string(key)]; !ok {
+				t.Errorf("index entry not reported %x", key)
+			}
+		}
+	}
+}

core/state/iterator.go

@@ -0,0 +1,143 @@
+// 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"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/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)
+	Entry  interface{} // Current state entry being iterated (internal representation)
+	Parent common.Hash // Hash of the first full ancestor node (nil if current is the root)
+}
+
+// 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.
+func (it *NodeIterator) Next() bool {
+	it.step()
+	return it.retrieve()
+}
+
+// step moves the iterator to the next entry of the state trie.
+func (it *NodeIterator) step() {
+	// Abort if we reached the end of the iteration
+	if it.state == nil {
+		return
+	}
+	// Initialize the iterator if we've just started
+	if it.stateIt == nil {
+		it.stateIt = trie.NewNodeIterator(it.state.trie.Trie)
+	}
+	// If we had data nodes previously, we surely have at least state nodes
+	if it.dataIt != nil {
+		if cont := it.dataIt.Next(); !cont {
+			it.dataIt = nil
+		}
+		return
+	}
+	// If we had source code previously, discard that
+	if it.code != nil {
+		it.code = nil
+		return
+	}
+	// Step to the next state trie node, terminating if we're out of nodes
+	if cont := it.stateIt.Next(); !cont {
+		it.state, it.stateIt = nil, nil
+		return
+	}
+	// If the state trie node is an internal entry, leave as is
+	if !it.stateIt.Leaf {
+		return
+	}
+	// Otherwise we've reached an account node, initiate data iteration
+	var account struct {
+		Nonce    uint64
+		Balance  *big.Int
+		Root     common.Hash
+		CodeHash []byte
+	}
+	err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob), &account)
+	if err != nil {
+		panic(err)
+	}
+	dataTrie, err := trie.New(account.Root, it.state.db)
+	if err != nil {
+		panic(err)
+	}
+	it.dataIt = trie.NewNodeIterator(dataTrie)
+	if !it.dataIt.Next() {
+		it.dataIt = nil
+	}
+	if bytes.Compare(account.CodeHash, emptyCodeHash) != 0 {
+		it.codeHash = common.BytesToHash(account.CodeHash)
+		it.code, err = it.state.db.Get(account.CodeHash)
+		if err != nil {
+			panic(fmt.Sprintf("code %x: %v", account.CodeHash, err))
+		}
+	}
+	it.accountHash = it.stateIt.Parent
+}
+
+// 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, it.Entry = common.Hash{}, nil
+
+	// 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.Entry, it.Parent = it.dataIt.Hash, it.dataIt.Node, it.dataIt.Parent
+		if it.Parent == (common.Hash{}) {
+			it.Parent = it.accountHash
+		}
+	case it.code != nil:
+		it.Hash, it.Entry, it.Parent = it.codeHash, it.code, it.accountHash
+	case it.stateIt != nil:
+		it.Hash, it.Entry, it.Parent = it.stateIt.Hash, it.stateIt.Node, it.stateIt.Parent
+	}
+	return true
+}

core/state/iterator_test.go

@@ -0,0 +1,61 @@
+// 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"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// Tests that the node iterator indeed walks over the entire database contents.
+func TestNodeIteratorCoverage(t *testing.T) {
+	// Create some arbitrary test state to iterate
+	db, root, _ := makeTestState()
+
+	state, err := New(root, db)
+	if err != nil {
+		t.Fatalf("failed to create state trie at %x: %v", root, err)
+	}
+	// Gather all the node hashes found by the iterator
+	hashes := make(map[common.Hash]struct{})
+	for it := NewNodeIterator(state); it.Next(); {
+		if it.Hash != (common.Hash{}) {
+			hashes[it.Hash] = struct{}{}
+		}
+	}
+	// Cross check the hashes and the database itself
+	for hash, _ := range hashes {
+		if _, err := db.Get(hash.Bytes()); err != nil {
+			t.Errorf("failed to retrieve reported node %x: %v", hash, err)
+		}
+	}
+	for _, key := range db.(*ethdb.MemDatabase).Keys() {
+		if bytes.HasPrefix(key, []byte("secure-key-")) {
+			continue
+		}
+		if bytes.HasPrefix(key, trie.ParentReferenceIndexPrefix) {
+			continue
+		}
+		if _, ok := hashes[common.BytesToHash(key)]; !ok {
+			t.Errorf("state entry not reported %x", key)
+		}
+	}
+}

core/state/state_object.go

@@ -118,7 +118,7 @@ func (c *StateObject) setAddr(addr []byte, value common.Hash) {
 		// if RLPing failed we better panic and not fail silently. This would be considered a consensus issue
 		panic(err)
 	}
-	c.trie.Update(addr, v)
+	c.trie.UpdateIndexed(addr, v, nil)
 }
 
 func (self *StateObject) Storage() Storage {

core/state/statedb.go

@@ -206,15 +206,17 @@ func (self *StateDB) Delete(addr common.Address) bool {
 
 // Update the given state object and apply it to state trie
 func (self *StateDB) UpdateStateObject(stateObject *StateObject) {
+	refs := [][]byte{stateObject.Root()}
 	if len(stateObject.code) > 0 {
 		self.db.Put(stateObject.codeHash, stateObject.code)
+		refs = append(refs, stateObject.codeHash)
 	}
 	addr := stateObject.Address()
 	data, err := rlp.EncodeToBytes(stateObject)
 	if err != nil {
 		panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err))
 	}
-	self.trie.Update(addr[:], data)
+	self.trie.UpdateIndexed(addr[:], data, refs)
 }
 
 // Delete the given state object and delete it from the state trie

core/state/sync_test.go

@@ -18,10 +18,12 @@ package state
 
 import (
 	"bytes"
+	"fmt"
 	"math/big"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/trie"
 )
@@ -42,7 +44,7 @@ func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
 
 	// Fill it with some arbitrary data
 	accounts := []*testAccount{}
-	for i := byte(0); i < 255; i++ {
+	for i := byte(0); i < 96; i++ {
 		obj := state.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
 		acc := &testAccount{address: common.BytesToAddress([]byte{i})}
 
@@ -61,6 +63,9 @@ func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
 	}
 	root, _ := state.Commit()
 
+	// Remove any potentially cached data from the test state creation
+	trie.ClearGlobalCache()
+
 	// Return the generated state
 	return db, root, accounts
 }
@@ -68,9 +73,21 @@ func makeTestState() (ethdb.Database, common.Hash, []*testAccount) {
 // checkStateAccounts cross references a reconstructed state with an expected
 // account array.
 func checkStateAccounts(t *testing.T, db ethdb.Database, root common.Hash, accounts []*testAccount) {
-	state, _ := New(root, db)
+	// Remove any potentially cached data from the state synchronisation
-	for i, acc := range accounts {
+	trie.ClearGlobalCache()
 
+	// Check root availability and state contents
+	state, err := New(root, db)
+	if err != nil {
+		t.Fatalf("failed to create state trie at %x: %v", root, err)
+	}
+	if err := checkStateConsistency(db, root); err != nil {
+		t.Fatalf("inconsistent state trie at %x: %v", root, err)
+	}
+	if err := checkStateIndex(db, root); err != nil {
+		t.Fatalf("index error at %x: %v", root, err)
+	}
+	for i, acc := range accounts {
 		if balance := state.GetBalance(acc.address); balance.Cmp(acc.balance) != 0 {
 			t.Errorf("account %d: balance mismatch: have %v, want %v", i, balance, acc.balance)
 		}
@@ -83,6 +100,55 @@ func checkStateAccounts(t *testing.T, db ethdb.Database, root common.Hash, accou
 	}
 }
 
+// checkStateConsistency checks that all nodes in a state trie and indeed present.
+func checkStateConsistency(db ethdb.Database, root common.Hash) (failure error) {
+	// Capture any panics by the iterator
+	defer func() {
+		if r := recover(); r != nil {
+			failure = fmt.Errorf("%v", r)
+		}
+	}()
+	// Remove any potentially cached data from the test state creation or previous checks
+	trie.ClearGlobalCache()
+
+	// Create and iterate a state trie rooted in a sub-node
+	if _, err := db.Get(root.Bytes()); err != nil {
+		return
+	}
+	state, err := New(root, db)
+	if err != nil {
+		return
+	}
+	for it := NewNodeIterator(state); it.Next(); {
+	}
+	return nil
+}
+
+// checkStateIndex iterates over the entire state trie and checks that all required
+// database indexes have been generated by the synchronizer.
+func checkStateIndex(db ethdb.Database, root common.Hash) error {
+	// Remove any potentially cached data from the test state creation or previous checks
+	trie.ClearGlobalCache()
+
+	// Create and iterate a state trie rooted in a sub-node
+	if _, err := db.Get(root.Bytes()); err != nil {
+		return err
+	}
+	state, err := New(root, db)
+	if err != nil {
+		return err
+	}
+	for it := NewNodeIterator(state); it.Next(); {
+		if (it.Hash != common.Hash{}) && (it.Parent != common.Hash{}) {
+			parentRef := trie.ParentReferenceIndexKey(it.Parent.Bytes(), it.Hash.Bytes())
+			if _, err := db.Get(parentRef); err != nil {
+				return fmt.Errorf("parent reference lookup %x: %v", parentRef, err)
+			}
+		}
+	}
+	return nil
+}
+
 // Tests that an empty state is not scheduled for syncing.
 func TestEmptyStateSync(t *testing.T) {
 	empty := common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
@@ -236,3 +302,65 @@ func TestIterativeRandomDelayedStateSync(t *testing.T) {
 	// Cross check that the two states are in sync
 	checkStateAccounts(t, dstDb, srcRoot, srcAccounts)
 }
+
+// Tests that at any point in time during a sync, only complete sub-tries are in
+// the database.
+func TestIncompleteStateSync(t *testing.T) {
+	// Create a random state to copy
+	srcDb, srcRoot, srcAccounts := makeTestState()
+
+	// Create a destination state and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewStateSync(srcRoot, dstDb)
+
+	added := []common.Hash{}
+	queue := append([]common.Hash{}, sched.Missing(1)...)
+	for len(queue) > 0 {
+		// Fetch a batch of state nodes
+		results := make([]trie.SyncResult, len(queue))
+		for i, hash := range queue {
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results[i] = trie.SyncResult{hash, data}
+		}
+		// Process each of the state nodes
+		if index, err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process result #%d: %v", index, err)
+		}
+		for _, result := range results {
+			added = append(added, result.Hash)
+		}
+		// Check that all known sub-tries in the synced state is complete
+		for _, root := range added {
+			// Skim through the accounts and make sure the root hash is not a code node
+			codeHash := false
+			for _, acc := range srcAccounts {
+				if bytes.Compare(root.Bytes(), crypto.Sha3(acc.code)) == 0 {
+					codeHash = true
+					break
+				}
+			}
+			// If the root is a real trie node, check consistency
+			if !codeHash {
+				if err := checkStateConsistency(dstDb, root); err != nil {
+					t.Fatalf("state inconsistent: %v", err)
+				}
+			}
+		}
+		// Fetch the next batch to retrieve
+		queue = append(queue[:0], sched.Missing(1)...)
+	}
+	// Sanity check that removing any node from the database is detected
+	for _, node := range added[1:] {
+		key := node.Bytes()
+		value, _ := dstDb.Get(key)
+
+		dstDb.Delete(key)
+		if err := checkStateConsistency(dstDb, added[0]); err == nil {
+			t.Fatalf("trie inconsistency not caught, missing: %x", key)
+		}
+		dstDb.Put(key, value)
+	}
+}

core/types/derive_sha.go

@@ -35,7 +35,7 @@ func DeriveSha(list DerivableList) common.Hash {
 	for i := 0; i < list.Len(); i++ {
 		keybuf.Reset()
 		rlp.Encode(keybuf, uint(i))
-		trie.Update(keybuf.Bytes(), list.GetRlp(i))
+		trie.UpdateIndexed(keybuf.Bytes(), list.GetRlp(i), nil)
 	}
 	return trie.Hash()
 }

core/vm/contract.go

@@ -27,6 +27,7 @@ type ContractRef interface {
 	ReturnGas(*big.Int, *big.Int)
 	Address() common.Address
 	SetCode([]byte)
+	EachStorage(cb func(key, value []byte))
 }
 
 // Contract represents an ethereum contract in the state database. It contains
@@ -124,3 +125,9 @@ func (self *Contract) SetCallCode(addr *common.Address, code []byte) {
 	self.Code = code
 	self.CodeAddr = addr
 }
+
+// EachStorage iterates the contract's storage and calls a method for every key
+// value pair.
+func (self *Contract) EachStorage(cb func(key, value []byte)) {
+	self.caller.EachStorage(cb)
+}

core/vm/environment.go

@@ -121,4 +121,5 @@ type Account interface {
 	Address() common.Address
 	ReturnGas(*big.Int, *big.Int)
 	SetCode([]byte)
+	EachStorage(cb func(key, value []byte))
 }

core/vm/jit_test.go

@@ -133,6 +133,7 @@ func (account) Balance() *big.Int            { return nil }
 func (account) Address() common.Address                { return common.Address{} }
 func (account) ReturnGas(*big.Int, *big.Int)           {}
 func (account) SetCode([]byte)                         {}
+func (account) EachStorage(cb func(key, value []byte)) {}
 
 func runVmBench(test vmBench, b *testing.B) {
 	var sender account

core/vm/vm.go

@@ -376,12 +376,9 @@ func (self *Vm) log(pc uint64, op OpCode, gas, cost *big.Int, memory *Memory, st
 			stck[i] = new(big.Int).Set(item)
 		}
 		storage := make(map[common.Hash][]byte)
-		/*
+		contract.self.EachStorage(func(k, v []byte) {
-			object := contract.self.(*state.StateObject)
-			object.EachStorage(func(k, v []byte) {
 			storage[common.BytesToHash(k)] = v
 		})
-		*/
 		self.env.AddStructLog(StructLog{pc, op, new(big.Int).Set(gas), cost, mem, stck, storage, err})
 	}
 }

trie/index.go

@@ -0,0 +1,68 @@
+// 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 trie
+
+import "bytes"
+
+var (
+	// ParentReferenceIndexPrefix is the database key prefix storing parent references index entries
+	ParentReferenceIndexPrefix = []byte("ref-")
+)
+
+// ParentReferenceIndexKey constructs a child->parent database index key.
+func ParentReferenceIndexKey(parent []byte, child []byte) []byte {
+	return append(append(ParentReferenceIndexPrefix, child...), parent...)
+}
+
+// storeParentReferences expands a trie node to find all its stored children and
+// adds a database reference pointing to the parent to permit reference tracking.
+func storeParentReferences(key []byte, node node, db DatabaseWriter) error {
+	switch node := node.(type) {
+	case fullNode:
+		for _, child := range node {
+			if child != nil {
+				if err := storeParentReferences(key, child, db); err != nil {
+					return err
+				}
+			}
+		}
+	case shortNode:
+		if child := node.Val; child != nil {
+			return storeParentReferences(key, child, db)
+		}
+	case hashNode:
+		return db.Put(ParentReferenceIndexKey(key, node), nil)
+
+	case valueNode:
+		for _, child := range node.refs {
+			if bytes.Compare(child, emptyRoot.Bytes()) == 0 {
+				continue // don't index an empty trie
+			}
+			if err := db.Put(ParentReferenceIndexKey(key, child), nil); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// storeParentReferenceEntry manually inserts a parent->child reference entry into
+// the database index without requiring direct, trie-internal descendancy. This is
+// useful to store references to external entities, like accounts or blocks.
+func storeParentReferenceEntry(parent []byte, child []byte, db DatabaseWriter) error {
+	return db.Put(ParentReferenceIndexKey(parent, child), nil)
+}

trie/index_test.go

@@ -0,0 +1,52 @@
+// 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 trie
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+// Tests that all index entries are stored in the database after a trie commit.
+func TestTrieIndex(t *testing.T) {
+	// Create some arbitrary test trie to iterate
+	db, trie, _ := makeTestTrie()
+
+	// Gather all the indexes that should be present in the database
+	indexes := make(map[string]struct{})
+	for it := NewNodeIterator(trie); it.Next(); {
+		if (it.Hash != common.Hash{}) && (it.Parent != common.Hash{}) {
+			indexes[string(ParentReferenceIndexKey(it.Parent.Bytes(), it.Hash.Bytes()))] = struct{}{}
+		}
+	}
+	// Cross check the indexes and the database itself
+	for index, _ := range indexes {
+		if _, err := db.Get([]byte(index)); err != nil {
+			t.Errorf("failed to retrieve reported index %x: %v", index, err)
+		}
+	}
+	for _, key := range db.(*ethdb.MemDatabase).Keys() {
+		if bytes.HasPrefix(key, ParentReferenceIndexPrefix) {
+			if _, ok := indexes[string(key)]; !ok {
+				t.Errorf("index entry not reported %x", key)
+			}
+		}
+	}
+}

trie/iterator.go

@@ -18,22 +18,27 @@ package trie
 
 import (
 	"bytes"
+	"fmt"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 )
 
+// Iterator is a key-value trie iterator to traverse the data contents.
 type Iterator struct {
 	trie *Trie
 
-	Key   []byte
+	Key   []byte // Current data key on which the iterator is positioned on
-	Value []byte
+	Value []byte // Current data value on which the iterator is positioned on
 }
 
+// NewIterator creates a new key-value iterator.
 func NewIterator(trie *Trie) *Iterator {
 	return &Iterator{trie: trie, Key: nil}
 }
 
+// Next moves the iterator forward with one key-value entry.
 func (self *Iterator) Next() bool {
 	isIterStart := false
 	if self.Key == nil {
@@ -81,11 +86,11 @@ func (self *Iterator) next(node interface{}, key []byte, isIterStart bool) []byt
 			switch bytes.Compare([]byte(k), key) {
 			case 0:
 				if isIterStart {
-					self.Value = vnode
+					self.Value = vnode.Value
 					return k
 				}
 			case 1:
-				self.Value = vnode
+				self.Value = vnode.Value
 				return k
 			}
 		} else {
@@ -120,13 +125,13 @@ func (self *Iterator) key(node interface{}) []byte {
 		// Leaf node
 		k := remTerm(node.Key)
 		if vnode, ok := node.Val.(valueNode); ok {
-			self.Value = vnode
+			self.Value = vnode.Value
 			return k
 		}
 		return append(k, self.key(node.Val)...)
 	case fullNode:
 		if node[16] != nil {
-			self.Value = node[16].(valueNode)
+			self.Value = node[16].(valueNode).Value
 			return []byte{16}
 		}
 		for i := 0; i < 16; i++ {
@@ -142,6 +147,126 @@ func (self *Iterator) key(node interface{}) []byte {
 		}
 		return self.key(rn)
 	}
-
 	return nil
 }
+
+// nodeIteratorState represents the iteration state at one particular node of the
+// trie, which can be resumed at a later invocation.
+type nodeIteratorState struct {
+	hash   common.Hash // Hash of the node being iterated (nil if not standalone)
+	node   node        // Trie node being iterated
+	parent common.Hash // Hash of the first full ancestor node (nil if current is the root)
+	child  int         // Child to be processed next
+}
+
+// NodeIterator is an iterator to traverse the trie post-order.
+type NodeIterator struct {
+	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)
+	Node     node        // Current node being iterated (internal representation)
+	Parent   common.Hash // Hash of the first full ancestor node (nil if current is the root)
+	Leaf     bool        // Flag whether the current node is a value (data) node
+	LeafBlob []byte      // Data blob contained within a leaf (otherwise nil)
+}
+
+// NewNodeIterator creates an post-order trie iterator.
+func NewNodeIterator(trie *Trie) *NodeIterator {
+	if bytes.Compare(trie.Root(), emptyRoot.Bytes()) == 0 {
+		return new(NodeIterator)
+	}
+	return &NodeIterator{trie: trie}
+}
+
+// Next moves the iterator to the next node, returning whether there are any
+// further nodes.
+func (it *NodeIterator) Next() bool {
+	it.step()
+	return it.retrieve()
+}
+
+// step moves the iterator to the next node of the trie.
+func (it *NodeIterator) step() {
+	// Abort if we reached the end of the iteration
+	if it.trie == nil {
+		return
+	}
+	// Initialize the iterator if we've just started, or pop off the old node otherwise
+	if len(it.stack) == 0 {
+		it.stack = append(it.stack, &nodeIteratorState{node: it.trie.root, child: -1})
+		if it.stack[0].node == nil {
+			panic(fmt.Sprintf("root node missing: %x", it.trie.Root()))
+		}
+	} else {
+		it.stack = it.stack[:len(it.stack)-1]
+		if len(it.stack) == 0 {
+			it.trie = nil
+			return
+		}
+	}
+	// Continue iteration to the next child
+	for {
+		parent := it.stack[len(it.stack)-1]
+		ancestor := parent.hash
+		if (ancestor == common.Hash{}) {
+			ancestor = parent.parent
+		}
+		if node, ok := parent.node.(fullNode); ok {
+			// Full node, traverse all children, then the node itself
+			if parent.child >= len(node) {
+				break
+			}
+			for parent.child++; parent.child < len(node); parent.child++ {
+				if current := node[parent.child]; current != nil {
+					it.stack = append(it.stack, &nodeIteratorState{node: current, parent: ancestor, child: -1})
+					break
+				}
+			}
+		} else if node, ok := parent.node.(shortNode); ok {
+			// Short node, traverse the pointer singleton child, then the node itself
+			if parent.child >= 0 {
+				break
+			}
+			parent.child++
+			it.stack = append(it.stack, &nodeIteratorState{node: node.Val, parent: ancestor, child: -1})
+		} else if hash, ok := parent.node.(hashNode); ok {
+			// Hash node, resolve the hash child from the database, then the node itself
+			if parent.child >= 0 {
+				break
+			}
+			parent.child++
+
+			node, err := it.trie.resolveHash(hash, nil, nil)
+			if err != nil {
+				panic(err)
+			}
+			it.stack = append(it.stack, &nodeIteratorState{hash: common.BytesToHash(hash), node: node, parent: ancestor, child: -1})
+		} else {
+			break
+		}
+	}
+}
+
+// retrieve pulls and caches the current trie node the iterator is traversing.
+// In case of a value node, the additional leaf blob is also populated with the
+// data contents for external interpretation.
+//
+// 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, it.Node, it.Parent, it.Leaf, it.LeafBlob = common.Hash{}, nil, common.Hash{}, false, nil
+
+	// If the iteration's done, return no available data
+	if it.trie == nil {
+		return false
+	}
+	// Otherwise retrieve the current node and resolve leaf accessors
+	state := it.stack[len(it.stack)-1]
+
+	it.Hash, it.Node, it.Parent = state.hash, state.node, state.parent
+	if node, ok := it.Node.(valueNode); ok {
+		it.Leaf, it.LeafBlob = true, []byte(node.Value)
+	}
+	return true
+}

trie/iterator_test.go

@@ -16,7 +16,12 @@
 
 package trie
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+)
 
 func TestIterator(t *testing.T) {
 	trie := newEmpty()
@@ -32,7 +37,7 @@ func TestIterator(t *testing.T) {
 	v := make(map[string]bool)
 	for _, val := range vals {
 		v[val.k] = false
-		trie.Update([]byte(val.k), []byte(val.v))
+		trie.UpdateIndexed([]byte(val.k), []byte(val.v), nil)
 	}
 	trie.Commit()
 
@@ -47,3 +52,30 @@ func TestIterator(t *testing.T) {
 		}
 	}
 }
+
+// Tests that the node iterator indeed walks over the entire database contents.
+func TestNodeIteratorCoverage(t *testing.T) {
+	// Create some arbitrary test trie to iterate
+	db, trie, _ := makeTestTrie()
+
+	// Gather all the node hashes found by the iterator
+	hashes := make(map[common.Hash]struct{})
+	for it := NewNodeIterator(trie); it.Next(); {
+		if it.Hash != (common.Hash{}) {
+			hashes[it.Hash] = struct{}{}
+		}
+	}
+	// Cross check the hashes and the database itself
+	for hash, _ := range hashes {
+		if _, err := db.Get(hash.Bytes()); err != nil {
+			t.Errorf("failed to retrieve reported node %x: %v", hash, err)
+		}
+	}
+	for _, key := range db.(*ethdb.MemDatabase).Keys() {
+		if len(key) == common.HashLength {
+			if _, ok := hashes[common.BytesToHash(key)]; !ok {
+				t.Errorf("state entry not reported %x", key)
+			}
+		}
+	}
+}

trie/node.go

@@ -38,9 +38,22 @@ type (
 		Val node
 	}
 	hashNode  []byte
-	valueNode []byte
+	valueNode struct {
+		Value []byte
+		refs  [][]byte
+	}
 )
 
+func (n valueNode) EncodeRLP(w io.Writer) error {
+	return rlp.Encode(w, n.Value)
+}
+
+func (n valueNode) DecodeRLP(s *rlp.Stream) (err error) {
+	fmt.Println("Decoding value node")
+	n.Value, err = s.Bytes()
+	return
+}
+
 // Pretty printing.
 func (n fullNode) String() string  { return n.fstring("") }
 func (n shortNode) String() string { return n.fstring("") }
@@ -65,7 +78,7 @@ func (n hashNode) fstring(ind string) string {
 	return fmt.Sprintf("<%x> ", []byte(n))
 }
 func (n valueNode) fstring(ind string) string {
-	return fmt.Sprintf("%x ", []byte(n))
+	return fmt.Sprintf("%x ", []byte(n.Value))
 }
 
 func mustDecodeNode(dbkey, buf []byte) node {
@@ -109,7 +122,7 @@ func decodeShort(buf []byte) (node, error) {
 		if err != nil {
 			return nil, fmt.Errorf("invalid value node: %v", err)
 		}
-		return shortNode{key, valueNode(val)}, nil
+		return shortNode{key, valueNode{Value: val}}, nil
 	}
 	r, _, err := decodeRef(rest)
 	if err != nil {
@@ -132,7 +145,7 @@ func decodeFull(buf []byte) (fullNode, error) {
 		return n, err
 	}
 	if len(val) > 0 {
-		n[16] = valueNode(val)
+		n[16] = valueNode{Value: val}
 	}
 	return n, nil
 }

trie/proof.go

@@ -107,7 +107,7 @@ func VerifyProof(rootHash common.Hash, key []byte, proof []rlp.RawValue) (value
 			if i != len(proof)-1 {
 				return nil, errors.New("additional nodes at end of proof")
 			}
-			return cld, nil
+			return cld.Value, nil
 		}
 	}
 	return nil, errors.New("unexpected end of proof")

trie/proof_test.go

@@ -119,14 +119,14 @@ func randomTrie(n int) (*Trie, map[string]*kv) {
 	for i := byte(0); i < 100; i++ {
 		value := &kv{common.LeftPadBytes([]byte{i}, 32), []byte{i}, false}
 		value2 := &kv{common.LeftPadBytes([]byte{i + 10}, 32), []byte{i}, false}
-		trie.Update(value.k, value.v)
+		trie.UpdateIndexed(value.k, value.v, nil)
-		trie.Update(value2.k, value2.v)
+		trie.UpdateIndexed(value2.k, value2.v, nil)
 		vals[string(value.k)] = value
 		vals[string(value2.k)] = value2
 	}
 	for i := 0; i < n; i++ {
 		value := &kv{randBytes(32), randBytes(20), false}
-		trie.Update(value.k, value.v)
+		trie.UpdateIndexed(value.k, value.v, nil)
 		vals[string(value.k)] = value
 	}
 	return trie, vals

trie/secure_trie.go

@@ -79,29 +79,27 @@ func (t *SecureTrie) TryGet(key []byte) ([]byte, error) {
 	return t.Trie.TryGet(t.hashKey(key))
 }
 
-// Update associates key with value in the trie. Subsequent calls to
+// UpdateIndexed is an extended version of Update, where state trie index entries
-// Get will return value. If value has length zero, any existing value
+// are also generated for all entities referencing the current node.
-// is deleted from the trie and calls to Get will return nil.
 //
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
-func (t *SecureTrie) Update(key, value []byte) {
+func (t *SecureTrie) UpdateIndexed(key, value []byte, refs [][]byte) {
-	if err := t.TryUpdate(key, value); err != nil && glog.V(logger.Error) {
+	if err := t.TryUpdateIndexed(key, value, refs); err != nil && glog.V(logger.Error) {
 		glog.Errorf("Unhandled trie error: %v", err)
 	}
 }
 
-// TryUpdate associates key with value in the trie. Subsequent calls to
+// TryUpdateIndexed is an extended version of Update, where state trie index
-// Get will return value. If value has length zero, any existing value
+// entries are also generated for all entities referencing the current node.
-// is deleted from the trie and calls to Get will return nil.
 //
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
 //
 // If a node was not found in the database, a MissingNodeError is returned.
-func (t *SecureTrie) TryUpdate(key, value []byte) error {
+func (t *SecureTrie) TryUpdateIndexed(key, value []byte, refs [][]byte) error {
 	hk := t.hashKey(key)
-	err := t.Trie.TryUpdate(hk, value)
+	err := t.Trie.TryUpdateIndexed(hk, value, refs)
 	if err != nil {
 		return err
 	}

trie/secure_trie_test.go

@@ -45,7 +45,7 @@ func TestSecureDelete(t *testing.T) {
 	}
 	for _, val := range vals {
 		if val.v != "" {
-			trie.Update([]byte(val.k), []byte(val.v))
+			trie.UpdateIndexed([]byte(val.k), []byte(val.v), nil)
 		} else {
 			trie.Delete([]byte(val.k))
 		}
@@ -59,7 +59,7 @@ func TestSecureDelete(t *testing.T) {
 
 func TestSecureGetKey(t *testing.T) {
 	trie := newEmptySecure()
-	trie.Update([]byte("foo"), []byte("bar"))
+	trie.UpdateIndexed([]byte("foo"), []byte("bar"), nil)
 
 	key := []byte("foo")
 	value := []byte("bar")

trie/sync.go

@@ -34,6 +34,8 @@ type request struct {
 	depth   int        // Depth level within the trie the node is located to prioritise DFS
 	deps    int        // Number of dependencies before allowed to commit this node
 
+	externals []common.Hash // External children of this node to index in addition to internal ones
+
 	callback TrieSyncLeafCallback // Callback to invoke if a leaf node it reached on this branch
 }
 
@@ -94,6 +96,7 @@ func (s *TrieSync) AddSubTrie(root common.Hash, depth int, parent common.Hash, c
 			panic(fmt.Sprintf("sub-trie ancestor not found: %x", parent))
 		}
 		ancestor.deps++
+		ancestor.externals = append(ancestor.externals, root)
 		req.parents = append(req.parents, ancestor)
 	}
 	s.schedule(req)
@@ -123,6 +126,7 @@ func (s *TrieSync) AddRawEntry(hash common.Hash, depth int, parent common.Hash)
 			panic(fmt.Sprintf("raw-entry ancestor not found: %x", parent))
 		}
 		ancestor.deps++
+		ancestor.externals = append(ancestor.externals, hash)
 		req.parents = append(req.parents, ancestor)
 	}
 	s.schedule(req)
@@ -229,7 +233,7 @@ func (s *TrieSync) children(req *request) ([]*request, error) {
 		// Notify any external watcher of a new key/value node
 		if req.callback != nil {
 			if node, ok := (*child.node).(valueNode); ok {
-				if err := req.callback(node, req.hash); err != nil {
+				if err := req.callback(node.Value, req.hash); err != nil {
 					return nil, err
 				}
 			}
@@ -266,7 +270,17 @@ func (s *TrieSync) commit(req *request, batch ethdb.Batch) (err error) {
 			err = batch.Write()
 		}()
 	}
-	// Write the node content to disk
+	// Write the node content and indices to disk
+	if req.object != nil {
+		if err := storeParentReferences(req.hash[:], *req.object, batch); err != nil {
+			return err
+		}
+	}
+	for _, ext := range req.externals {
+		if err := storeParentReferenceEntry(req.hash[:], ext[:], batch); err != nil {
+			return err
+		}
+	}
 	if err := batch.Put(req.hash[:], req.data); err != nil {
 		return err
 	}

trie/sync_test.go

@@ -18,6 +18,7 @@ package trie
 
 import (
 	"bytes"
+	"fmt"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -33,16 +34,27 @@ func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
 	// Fill it with some arbitrary data
 	content := make(map[string][]byte)
 	for i := byte(0); i < 255; i++ {
+		// Map the same data under multiple keys
 		key, val := common.LeftPadBytes([]byte{1, i}, 32), []byte{i}
 		content[string(key)] = val
-		trie.Update(key, val)
+		trie.UpdateIndexed(key, val, nil)
 
 		key, val = common.LeftPadBytes([]byte{2, i}, 32), []byte{i}
 		content[string(key)] = val
-		trie.Update(key, val)
+		trie.UpdateIndexed(key, val, nil)
+
+		// Add some other data to inflate th trie
+		for j := byte(3); j < 13; j++ {
+			key, val = common.LeftPadBytes([]byte{j, i}, 32), []byte{j, i}
+			content[string(key)] = val
+			trie.UpdateIndexed(key, val, nil)
+		}
 	}
 	trie.Commit()
 
+	// Remove any potentially cached data from the test trie creation
+	globalCache.Clear()
+
 	// Return the generated trie
 	return db, trie, content
 }
@@ -50,10 +62,20 @@ func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
 // checkTrieContents cross references a reconstructed trie with an expected data
 // content map.
 func checkTrieContents(t *testing.T, db Database, root []byte, content map[string][]byte) {
+	// Remove any potentially cached data from the trie synchronisation
+	globalCache.Clear()
+
+	// Check root availability and trie contents
 	trie, err := New(common.BytesToHash(root), db)
 	if err != nil {
 		t.Fatalf("failed to create trie at %x: %v", root, err)
 	}
+	if err := checkTrieConsistency(db, common.BytesToHash(root)); err != nil {
+		t.Fatalf("inconsistent trie at %x: %v", root, err)
+	}
+	if err := checkTrieIndex(db, common.BytesToHash(root)); err != nil {
+		t.Fatalf("index error at %x: %v", root, err)
+	}
 	for key, val := range content {
 		if have := trie.Get([]byte(key)); bytes.Compare(have, val) != 0 {
 			t.Errorf("entry %x: content mismatch: have %x, want %x", key, have, val)
@@ -61,6 +83,49 @@ func checkTrieContents(t *testing.T, db Database, root []byte, content map[strin
 	}
 }
 
+// checkTrieConsistency checks that all nodes in a trie and indeed present.
+func checkTrieConsistency(db Database, root common.Hash) (failure error) {
+	// Capture any panics by the iterator
+	defer func() {
+		if r := recover(); r != nil {
+			failure = fmt.Errorf("%v", r)
+		}
+	}()
+	// Remove any potentially cached data from the test trie creation or previous checks
+	globalCache.Clear()
+
+	// Create and iterate a trie rooted in a subnode
+	trie, err := New(root, db)
+	if err != nil {
+		return
+	}
+	for it := NewNodeIterator(trie); it.Next(); {
+	}
+	return nil
+}
+
+// checkTrieIndex iterates over the entire state trie and checks that all required
+// database indexes have been generated by the synchronizer.
+func checkTrieIndex(db Database, root common.Hash) error {
+	// Remove any potentially cached data from the test trie creation or previous checks
+	globalCache.Clear()
+
+	// Create and iterate a trie
+	trie, err := New(root, db)
+	if err != nil {
+		return err
+	}
+	for it := NewNodeIterator(trie); it.Next(); {
+		if (it.Hash != common.Hash{}) && (it.Parent != common.Hash{}) {
+			parentRef := ParentReferenceIndexKey(it.Parent.Bytes(), it.Hash.Bytes())
+			if _, err := db.Get(parentRef); err != nil {
+				return fmt.Errorf("parent reference lookup %x: %v", parentRef, err)
+			}
+		}
+	}
+	return nil
+}
+
 // Tests that an empty trie is not scheduled for syncing.
 func TestEmptyTrieSync(t *testing.T) {
 	emptyA, _ := New(common.Hash{}, nil)
@@ -102,7 +167,7 @@ func testIterativeTrieSync(t *testing.T, batch int) {
 		}
 		queue = append(queue[:0], sched.Missing(batch)...)
 	}
-	// Cross check that the two tries re in sync
+	// Cross check that the two tries are in sync
 	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
 }
 
@@ -132,7 +197,7 @@ func TestIterativeDelayedTrieSync(t *testing.T) {
 		}
 		queue = append(queue[len(results):], sched.Missing(10000)...)
 	}
-	// Cross check that the two tries re in sync
+	// Cross check that the two tries are in sync
 	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
 }
 
@@ -173,7 +238,7 @@ func testIterativeRandomTrieSync(t *testing.T, batch int) {
 			queue[hash] = struct{}{}
 		}
 	}
-	// Cross check that the two tries re in sync
+	// Cross check that the two tries are in sync
 	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
 }
 
@@ -216,7 +281,7 @@ func TestIterativeRandomDelayedTrieSync(t *testing.T) {
 			queue[hash] = struct{}{}
 		}
 	}
-	// Cross check that the two tries re in sync
+	// Cross check that the two tries are in sync
 	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
 }
 
@@ -252,6 +317,57 @@ func TestDuplicateAvoidanceTrieSync(t *testing.T) {
 		}
 		queue = append(queue[:0], sched.Missing(0)...)
 	}
-	// Cross check that the two tries re in sync
+	// Cross check that the two tries are in sync
 	checkTrieContents(t, dstDb, srcTrie.Root(), srcData)
 }
+
+// Tests that at any point in time during a sync, only complete sub-tries are in
+// the database.
+func TestIncompleteTrieSync(t *testing.T) {
+	// Create a random trie to copy
+	srcDb, srcTrie, _ := makeTestTrie()
+
+	// Create a destination trie and sync with the scheduler
+	dstDb, _ := ethdb.NewMemDatabase()
+	sched := NewTrieSync(common.BytesToHash(srcTrie.Root()), dstDb, nil)
+
+	added := []common.Hash{}
+	queue := append([]common.Hash{}, sched.Missing(1)...)
+	for len(queue) > 0 {
+		// Fetch a batch of trie nodes
+		results := make([]SyncResult, len(queue))
+		for i, hash := range queue {
+			data, err := srcDb.Get(hash.Bytes())
+			if err != nil {
+				t.Fatalf("failed to retrieve node data for %x: %v", hash, err)
+			}
+			results[i] = SyncResult{hash, data}
+		}
+		// Process each of the trie nodes
+		if index, err := sched.Process(results); err != nil {
+			t.Fatalf("failed to process result #%d: %v", index, err)
+		}
+		for _, result := range results {
+			added = append(added, result.Hash)
+		}
+		// Check that all known sub-tries in the synced trie is complete
+		for _, root := range added {
+			if err := checkTrieConsistency(dstDb, root); err != nil {
+				t.Fatalf("trie inconsistent: %v", err)
+			}
+		}
+		// Fetch the next batch to retrieve
+		queue = append(queue[:0], sched.Missing(1)...)
+	}
+	// Sanity check that removing any node from the database is detected
+	for _, node := range added[1:] {
+		key := node.Bytes()
+		value, _ := dstDb.Get(key)
+
+		dstDb.Delete(key)
+		if err := checkTrieConsistency(dstDb, added[0]); err == nil {
+			t.Fatalf("trie inconsistency not caught, missing: %x", key)
+		}
+		dstDb.Put(key, value)
+	}
+}

trie/trie.go

@@ -143,33 +143,35 @@ func (t *Trie) TryGet(key []byte) ([]byte, error) {
 			panic(fmt.Sprintf("%T: invalid node: %v", tn, tn))
 		}
 	}
-	return tn.(valueNode), nil
+	return tn.(valueNode).Value, nil
 }
 
-// Update associates key with value in the trie. Subsequent calls to
+// UpdateIndexed is an extended version of Update, where state trie index entries
-// Get will return value. If value has length zero, any existing value
+// are also generated for all entities referencing the current node.
-// is deleted from the trie and calls to Get will return nil.
 //
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
-func (t *Trie) Update(key, value []byte) {
+func (t *Trie) UpdateIndexed(key, value []byte, refs [][]byte) {
-	if err := t.TryUpdate(key, value); err != nil && glog.V(logger.Error) {
+	if err := t.TryUpdateIndexed(key, value, refs); err != nil && glog.V(logger.Error) {
 		glog.Errorf("Unhandled trie error: %v", err)
 	}
 }
 
-// TryUpdate associates key with value in the trie. Subsequent calls to
+// TryUpdateIndexed is an extended version of Update, where state trie index
-// Get will return value. If value has length zero, any existing value
+// entries are also generated for all entities referencing the current node.
-// is deleted from the trie and calls to Get will return nil.
 //
 // The value bytes must not be modified by the caller while they are
 // stored in the trie.
 //
 // If a node was not found in the database, a MissingNodeError is returned.
-func (t *Trie) TryUpdate(key, value []byte) error {
+func (t *Trie) TryUpdateIndexed(key, value []byte, refs [][]byte) error {
+	return t.tryUpdateIndexed(key, value, refs)
+}
+
+func (t *Trie) tryUpdateIndexed(key, value []byte, refs [][]byte) error {
 	k := compactHexDecode(key)
 	if len(value) != 0 {
-		n, err := t.insert(t.root, nil, k, valueNode(value))
+		n, err := t.insert(t.root, nil, k, valueNode{Value: value, refs: refs})
 		if err != nil {
 			return err
 		}
@@ -489,7 +491,7 @@ func (h *hasher) replaceChildren(n node, db DatabaseWriter) (node, error) {
 		}
 		if n.Val == nil {
 			// Ensure that nil children are encoded as empty strings.
-			n.Val = valueNode(nil)
+			n.Val = valueNode{Value: nil}
 		}
 		return n, nil
 	case fullNode:
@@ -500,11 +502,11 @@ func (h *hasher) replaceChildren(n node, db DatabaseWriter) (node, error) {
 				}
 			} else {
 				// Ensure that nil children are encoded as empty strings.
-				n[i] = valueNode(nil)
+				n[i] = valueNode{Value: nil}
 			}
 		}
 		if n[16] == nil {
-			n[16] = valueNode(nil)
+			n[16] = valueNode{Value: nil}
 		}
 		return n, nil
 	default:
@@ -530,8 +532,13 @@ func (h *hasher) store(n node, db DatabaseWriter, force bool) (node, error) {
 	h.sha.Write(h.tmp.Bytes())
 	key := hashNode(h.sha.Sum(nil))
 	if db != nil {
-		err := db.Put(key, h.tmp.Bytes())
+		if err := storeParentReferences(key, n, db); err != nil {
+			return key, err
+		}
+		if err := db.Put(key, h.tmp.Bytes()); err != nil {
 			return key, err
 		}
 		return key, nil
+	}
+	return key, nil
 }

trie/trie_test.go

@@ -54,7 +54,7 @@ func TestNull(t *testing.T) {
 	var trie Trie
 	key := make([]byte, 32)
 	value := common.FromHex("0x823140710bf13990e4500136726d8b55")
-	trie.Update(key, value)
+	trie.UpdateIndexed(key, value, nil)
 	value = trie.Get(key)
 }
 
@@ -97,7 +97,7 @@ func TestMissingNode(t *testing.T) {
 	}
 
 	trie, _ = New(root, db)
-	err = trie.TryUpdate([]byte("120099"), []byte("zxcvzxcvzxcvzxcvzxcvzxcvzxcvzxcv"))
+	err = trie.TryUpdateIndexed([]byte("120099"), []byte("zxcvzxcvzxcvzxcvzxcvzxcvzxcvzxcv"), nil)
 	if err != nil {
 		t.Errorf("Unexpected error: %v", err)
 	}
@@ -130,7 +130,7 @@ func TestMissingNode(t *testing.T) {
 	}
 
 	trie, _ = New(root, db)
-	err = trie.TryUpdate([]byte("120099"), []byte("zxcv"))
+	err = trie.TryUpdateIndexed([]byte("120099"), []byte("zxcv"), nil)
 	if _, ok := err.(*MissingNodeError); !ok {
 		t.Errorf("Wrong error: %v", err)
 	}
@@ -304,7 +304,7 @@ func paranoiaCheck(t1 *Trie) (bool, *Trie) {
 	t2 := new(Trie)
 	it := NewIterator(t1)
 	for it.Next() {
-		t2.Update(it.Key, it.Value)
+		t2.UpdateIndexed(it.Key, it.Value, nil)
 	}
 	return t2.Hash() == t1.Hash(), t2
 }
@@ -356,8 +356,8 @@ func TestOutput(t *testing.T) {
 
 func TestLargeValue(t *testing.T) {
 	trie := newEmpty()
-	trie.Update([]byte("key1"), []byte{99, 99, 99, 99})
+	trie.UpdateIndexed([]byte("key1"), []byte{99, 99, 99, 99}, nil)
-	trie.Update([]byte("key2"), bytes.Repeat([]byte{1}, 32))
+	trie.UpdateIndexed([]byte("key2"), bytes.Repeat([]byte{1}, 32), nil)
 	trie.Hash()
 
 }
@@ -374,8 +374,8 @@ func TestLargeData(t *testing.T) {
 	for i := byte(0); i < 255; i++ {
 		value := &kv{common.LeftPadBytes([]byte{i}, 32), []byte{i}, false}
 		value2 := &kv{common.LeftPadBytes([]byte{10, i}, 32), []byte{i}, false}
-		trie.Update(value.k, value.v)
+		trie.UpdateIndexed(value.k, value.v, nil)
-		trie.Update(value2.k, value2.v)
+		trie.UpdateIndexed(value2.k, value2.v, nil)
 		vals[string(value.k)] = value
 		vals[string(value2.k)] = value2
 	}
@@ -419,7 +419,7 @@ func benchGet(b *testing.B, commit bool) {
 	k := make([]byte, 32)
 	for i := 0; i < benchElemCount; i++ {
 		binary.LittleEndian.PutUint64(k, uint64(i))
-		trie.Update(k, k)
+		trie.UpdateIndexed(k, k, nil)
 	}
 	binary.LittleEndian.PutUint64(k, benchElemCount/2)
 	if commit {
@@ -437,7 +437,7 @@ func benchUpdate(b *testing.B, e binary.ByteOrder) *Trie {
 	k := make([]byte, 32)
 	for i := 0; i < b.N; i++ {
 		e.PutUint64(k, uint64(i))
-		trie.Update(k, k)
+		trie.UpdateIndexed(k, k, nil)
 	}
 	return trie
 }
@@ -447,7 +447,7 @@ func benchHash(b *testing.B, e binary.ByteOrder) {
 	k := make([]byte, 32)
 	for i := 0; i < benchElemCount; i++ {
 		e.PutUint64(k, uint64(i))
-		trie.Update(k, k)
+		trie.UpdateIndexed(k, k, nil)
 	}
 
 	b.ResetTimer()
@@ -473,7 +473,7 @@ func getString(trie *Trie, k string) []byte {
 }
 
 func updateString(trie *Trie, k, v string) {
-	trie.Update([]byte(k), []byte(v))
+	trie.UpdateIndexed([]byte(k), []byte(v), nil)
 }
 
 func deleteString(trie *Trie, k string) {