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core/state, trie: add node iterator, test state/trie sync consistency

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This commit is contained in:
Péter Szilágyi
2015-12-28 15:20:37 +02:00
parent 4f28c5b69d
commit 7e29b0b5b4
4 changed files with 451 additions and 11 deletions
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120
trie/iterator.go
View File

@ -18,22 +18,26 @@ package trie
import (
"bytes"
"fmt"
"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
Value []byte
Key []byte // Current data key on which the iterator is positioned on
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 {
@ -142,6 +146,116 @@ 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 {
node node // Trie node being iterated
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
Node node // Current node being iterated (internal representation)
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]
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, 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, child: -1})
} else if node, 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(node, nil, nil)
if err != nil {
panic(err)
}
it.stack = append(it.stack, &nodeIteratorState{node: node, 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.Node, it.Leaf, it.LeafBlob = nil, 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
it.Node = it.stack[len(it.stack)-1].node
if value, ok := it.Node.(valueNode); ok {
it.Leaf, it.LeafBlob = true, []byte(value)
}
return true
}

102
trie/sync_test.go
View File

@ -18,6 +18,7 @@ package trie
import (
"bytes"
"fmt"
"testing"
"github.com/ethereum/go-ethereum/common"
@ -33,6 +34,7 @@ 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)
@ -40,9 +42,19 @@ func makeTestTrie() (ethdb.Database, *Trie, map[string][]byte) {
key, val = common.LeftPadBytes([]byte{2, i}, 32), []byte{i}
content[string(key)] = val
trie.Update(key, val)
// 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.Update(key, val)
}
}
trie.Commit()
// Remove any potentially cached data from the test trie creation
globalCache.Clear()
// Return the generated trie
return db, trie, content
}
@ -50,10 +62,17 @@ 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)
}
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 +80,28 @@ 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
}
it := NewNodeIterator(trie)
for it.Next() {
}
return nil
}
// Tests that an empty trie is not scheduled for syncing.
func TestEmptyTrieSync(t *testing.T) {
emptyA, _ := New(common.Hash{}, nil)
@ -102,7 +143,7 @@ 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 +173,7 @@ 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 +214,7 @@ 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 +257,7 @@ 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 +293,57 @@ 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)
}
}