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core/state, trie: Rewrite NodeIterator as an interface

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This commit is contained in:
Nick Johnson 2017-01-17 14:47:35 +00:00
parent 2b78c04da0
commit f105ac0644
5 changed files with 93 additions and 62 deletions
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27
core/state/iterator.go
View file

@ -31,15 +31,14 @@ import (
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
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)
Error error // Failure set in case of an internal error in the iterator
@ -81,8 +80,8 @@ func (it *NodeIterator) step() error {
// 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
if it.dataIt.Error() != nil {
return it.dataIt.Error()
}
it.dataIt = nil
}
@ -95,14 +94,14 @@ func (it *NodeIterator) step() error {
}
// 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
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 {
if !it.stateIt.Leaf() {
return nil
}
// Otherwise we've reached an account node, initiate data iteration
@ -112,7 +111,7 @@ func (it *NodeIterator) step() error {
Root common.Hash
CodeHash []byte
}
if err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob), &account); err != nil {
if err := rlp.Decode(bytes.NewReader(it.stateIt.LeafBlob()), &account); err != nil {
return err
}
dataTrie, err := trie.New(account.Root, it.state.db)
@ -130,7 +129,7 @@ func (it *NodeIterator) step() error {
return fmt.Errorf("code %x: %v", account.CodeHash, err)
}
}
it.accountHash = it.stateIt.Parent
it.accountHash = it.stateIt.Parent()
return nil
}
@ -138,7 +137,7 @@ func (it *NodeIterator) step() error {
// 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
it.Hash = common.Hash{}
// If the iteration's done, return no available data
if it.state == nil {
@ -147,14 +146,14 @@ func (it *NodeIterator) retrieve() bool {
// 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
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.Entry, it.Parent = it.codeHash, it.code, it.accountHash
it.Hash, it.Parent = it.codeHash, it.accountHash
case it.stateIt != nil:
it.Hash, it.Entry, it.Parent = it.stateIt.Hash, it.stateIt.Node, it.stateIt.Parent
it.Hash, it.Parent = it.stateIt.Hash(), it.stateIt.Parent()
}
return true
}

120
trie/iterator.go
View file

@ -21,7 +21,7 @@ import "github.com/ethereum/go-ethereum/common"
// Iterator is a key-value trie iterator that traverses a Trie.
type Iterator struct {
trie *Trie
nodeIt *NodeIterator
nodeIt NodeIterator
Key []byte // Current data key on which the iterator is positioned on
Value []byte // Current data value on which the iterator is positioned on
@ -39,9 +39,9 @@ func NewIterator(trie *Trie) *Iterator {
// Next moves the iterator forward one key-value entry.
func (it *Iterator) Next() bool {
for it.nodeIt.Next(true) {
if it.nodeIt.Leaf {
it.Key = decodeCompact(it.nodeIt.path)
it.Value = it.nodeIt.LeafBlob
if it.nodeIt.Leaf() {
it.Key = decodeCompact(it.nodeIt.Path())
it.Value = it.nodeIt.LeafBlob()
return true
}
}
@ -50,6 +50,17 @@ func (it *Iterator) Next() bool {
return false
}
// NodeIterator is an iterator to traverse the trie pre-order.
type NodeIterator interface {
Hash() common.Hash
Parent() common.Hash
Leaf() bool
LeafBlob() []byte
Path() []byte
Next(bool) bool
Error() error
}
// nodeIteratorState represents the iteration state at one particular node of the
// trie, which can be resumed at a later invocation.
type nodeIteratorState struct {
@ -60,48 +71,92 @@ type nodeIteratorState struct {
pathlen int // Length of the path to this node
}
// NodeIterator is an iterator to traverse the trie post-order.
type NodeIterator struct {
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)
path []byte // Path to the current node
err error // Failure set in case of an internal error in the iterator
Error error // Failure set in case of an internal error in the iterator
path []byte // Path to the current node
}
// NewNodeIterator creates an post-order trie iterator.
func NewNodeIterator(trie *Trie) *NodeIterator {
func NewNodeIterator(trie *Trie) NodeIterator {
if trie.Hash() == emptyState {
return new(NodeIterator)
return new(nodeIterator)
}
return &NodeIterator{trie: trie}
return &nodeIterator{trie: trie}
}
// Hash returns the hash of the current node
func (it *nodeIterator) Hash() common.Hash {
if it.trie == nil {
return common.Hash{}
}
return it.stack[len(it.stack)-1].hash
}
// Parent returns the hash of the parent node
func (it *nodeIterator) Parent() common.Hash {
if it.trie == nil {
return common.Hash{}
}
return it.stack[len(it.stack)-1].parent
}
// Leaf returns true if the current node is a leaf
func (it *nodeIterator) Leaf() bool {
if it.trie == nil {
return false
}
_, ok := it.stack[len(it.stack)-1].node.(valueNode)
return ok
}
// LeafBlob returns the data for the current node, if it is a leaf
func (it *nodeIterator) LeafBlob() []byte {
if it.trie == nil {
return nil
}
if node, ok := it.stack[len(it.stack)-1].node.(valueNode); ok {
return []byte(node)
}
return nil
}
// Path returns the hex-encoded path to the current node
func (it *nodeIterator) Path() []byte {
return it.path
}
// Error returns the error set in case of an internal error in the iterator
func (it *nodeIterator) Error() error {
return it.err
}
// 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. If `children` is false,
// skips iterating over any subnodes of the current node.
func (it *NodeIterator) Next(children bool) bool {
func (it *nodeIterator) Next(children bool) bool {
// If the iterator failed previously, don't do anything
if it.Error != nil {
if it.err != nil {
return false
}
// Otherwise step forward with the iterator and report any errors
if err := it.step(children); err != nil {
it.Error = err
it.err = err
return false
}
return it.retrieve()
return it.trie != nil
}
// step moves the iterator to the next node of the trie.
func (it *NodeIterator) step(children bool) error {
func (it *nodeIterator) step(children bool) error {
if it.trie == nil {
// Abort if we reached the end of the iteration
return nil
@ -189,26 +244,3 @@ func (it *NodeIterator) step(children bool) error {
}
return nil
}
// 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 value, ok := it.Node.(valueNode); ok {
it.Leaf, it.LeafBlob = true, []byte(value)
}
return true
}

4
trie/iterator_test.go
View file

@ -100,8 +100,8 @@ func TestNodeIteratorCoverage(t *testing.T) {
// Gather all the node hashes found by the iterator
hashes := make(map[common.Hash]struct{})
for it := NewNodeIterator(trie); it.Next(true); {
if it.Hash != (common.Hash{}) {
hashes[it.Hash] = struct{}{}
if it.Hash() != (common.Hash{}) {
hashes[it.Hash()] = struct{}{}
}
}
// Cross check the hashes and the database itself

2
trie/secure_trie.go
View file

@ -159,7 +159,7 @@ func (t *SecureTrie) Iterator() *Iterator {
return t.trie.Iterator()
}
func (t *SecureTrie) NodeIterator() *NodeIterator {
func (t *SecureTrie) NodeIterator() NodeIterator {
return NewNodeIterator(&t.trie)
}

2
trie/sync_test.go
View file

@ -83,7 +83,7 @@ func checkTrieConsistency(db Database, root common.Hash) error {
it := NewNodeIterator(trie)
for it.Next(true) {
}
return it.Error
return it.Error()
}
// Tests that an empty trie is not scheduled for syncing.