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-rw-r--r--trie/iterator.go355
1 files changed, 248 insertions, 107 deletions
diff --git a/trie/iterator.go b/trie/iterator.go
index afde6e19e..234c49ecc 100644
--- a/trie/iterator.go
+++ b/trie/iterator.go
@@ -16,13 +16,14 @@
package trie
-import "github.com/ethereum/go-ethereum/common"
+import (
+ "bytes"
+ "github.com/ethereum/go-ethereum/common"
+)
// Iterator is a key-value trie iterator that traverses a Trie.
type Iterator struct {
- trie *Trie
- nodeIt *NodeIterator
- keyBuf []byte
+ 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
@@ -31,19 +32,23 @@ type Iterator struct {
// NewIterator creates a new key-value iterator.
func NewIterator(trie *Trie) *Iterator {
return &Iterator{
- trie: trie,
nodeIt: NewNodeIterator(trie),
- keyBuf: make([]byte, 0, 64),
- Key: nil,
+ }
+}
+
+// FromNodeIterator creates a new key-value iterator from a node iterator
+func NewIteratorFromNodeIterator(it NodeIterator) *Iterator {
+ return &Iterator{
+ nodeIt: it,
}
}
// Next moves the iterator forward one key-value entry.
func (it *Iterator) Next() bool {
- for it.nodeIt.Next() {
- if it.nodeIt.Leaf {
- it.Key = it.makeKey()
- it.Value = it.nodeIt.LeafBlob
+ for it.nodeIt.Next(true) {
+ if it.nodeIt.Leaf() {
+ it.Key = decodeCompact(it.nodeIt.Path())
+ it.Value = it.nodeIt.LeafBlob()
return true
}
}
@@ -52,74 +57,123 @@ func (it *Iterator) Next() bool {
return false
}
-func (it *Iterator) makeKey() []byte {
- key := it.keyBuf[:0]
- for _, se := range it.nodeIt.stack {
- switch node := se.node.(type) {
- case *fullNode:
- if se.child <= 16 {
- key = append(key, byte(se.child))
- }
- case *shortNode:
- if hasTerm(node.Key) {
- key = append(key, node.Key[:len(node.Key)-1]...)
- } else {
- key = append(key, node.Key...)
- }
- }
- }
- return decodeCompact(key)
+// NodeIterator is an iterator to traverse the trie pre-order.
+type NodeIterator interface {
+ // Hash returns the hash of the current node
+ Hash() common.Hash
+ // Parent returns the hash of the parent of the current node
+ Parent() common.Hash
+ // Leaf returns true iff the current node is a leaf node.
+ Leaf() bool
+ // LeafBlob returns the contents of the node, if it is a leaf.
+ // Callers must not retain references to the return value after calling Next()
+ LeafBlob() []byte
+ // Path returns the hex-encoded path to the current node.
+ // Callers must not retain references to the return value after calling Next()
+ Path() []byte
+ // Next moves the iterator to the next node. If the parameter is false, any child
+ // nodes will be skipped.
+ Next(bool) bool
+ // Error returns the error status of the iterator.
+ 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 {
- 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
+ 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
+ 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)
+ 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}
+}
+
+// Hash returns the hash of the current node
+func (it *nodeIterator) Hash() common.Hash {
+ if len(it.stack) == 0 {
+ 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 len(it.stack) == 0 {
+ 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 len(it.stack) == 0 {
+ return false
}
- return &NodeIterator{trie: trie}
+
+ _, 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 len(it.stack) == 0 {
+ 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.
-func (it *NodeIterator) Next() bool {
+// sets the Error field to the encountered failure. If `descend` is false,
+// skips iterating over any subnodes of the current node.
+func (it *nodeIterator) Next(descend 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(); err != nil {
- it.Error = err
+ if err := it.step(descend); err != nil {
+ 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() error {
+func (it *nodeIterator) step(descend bool) error {
if it.trie == nil {
// Abort if we reached the end of the iteration
return nil
@@ -132,93 +186,180 @@ func (it *NodeIterator) step() error {
state.hash = root
}
it.stack = append(it.stack, state)
- } else {
- // Continue iterating at the previous node otherwise.
+ return nil
+ }
+
+ if !descend {
+ // If we're skipping children, pop the current node first
+ it.path = it.path[:it.stack[len(it.stack)-1].pathlen]
it.stack = it.stack[:len(it.stack)-1]
- if len(it.stack) == 0 {
- it.trie = nil
- return nil
- }
}
// Continue iteration to the next child
+outer:
for {
+ if len(it.stack) == 0 {
+ it.trie = nil
+ return nil
+ }
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.Children) {
- break
- }
+ // Full node, iterate over children
for parent.child++; parent.child < len(node.Children); parent.child++ {
- if current := node.Children[parent.child]; current != nil {
+ child := node.Children[parent.child]
+ if child != nil {
+ hash, _ := child.cache()
it.stack = append(it.stack, &nodeIteratorState{
- hash: common.BytesToHash(node.flags.hash),
- node: current,
- parent: ancestor,
- child: -1,
+ hash: common.BytesToHash(hash),
+ node: child,
+ parent: ancestor,
+ child: -1,
+ pathlen: len(it.path),
})
- break
+ it.path = append(it.path, byte(parent.child))
+ break outer
}
}
} else if node, ok := parent.node.(*shortNode); ok {
- // Short node, traverse the pointer singleton child, then the node itself
- if parent.child >= 0 {
+ // Short node, return the pointer singleton child
+ if parent.child < 0 {
+ parent.child++
+ hash, _ := node.Val.cache()
+ it.stack = append(it.stack, &nodeIteratorState{
+ hash: common.BytesToHash(hash),
+ node: node.Val,
+ parent: ancestor,
+ child: -1,
+ pathlen: len(it.path),
+ })
+ if hasTerm(node.Key) {
+ it.path = append(it.path, node.Key[:len(node.Key)-1]...)
+ } else {
+ it.path = append(it.path, node.Key...)
+ }
break
}
- parent.child++
- it.stack = append(it.stack, &nodeIteratorState{
- hash: common.BytesToHash(node.flags.hash),
- 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 {
+ // Hash node, resolve the hash child from the database
+ if parent.child < 0 {
+ parent.child++
+ node, err := it.trie.resolveHash(hash, nil, nil)
+ if err != nil {
+ return err
+ }
+ it.stack = append(it.stack, &nodeIteratorState{
+ hash: common.BytesToHash(hash),
+ node: node,
+ parent: ancestor,
+ child: -1,
+ pathlen: len(it.path),
+ })
break
}
- parent.child++
-
- node, err := it.trie.resolveHash(hash, nil, nil)
- if err != nil {
- return err
- }
- it.stack = append(it.stack, &nodeIteratorState{
- hash: common.BytesToHash(hash),
- node: node,
- parent: ancestor,
- child: -1,
- })
- } else {
- break
}
+ it.path = it.path[:parent.pathlen]
+ it.stack = it.stack[:len(it.stack)-1]
}
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
+type differenceIterator struct {
+ a, b NodeIterator // Nodes returned are those in b - a.
+ eof bool // Indicates a has run out of elements
+ count int // Number of nodes scanned on either trie
+}
- // If the iteration's done, return no available data
- if it.trie == nil {
+// NewDifferenceIterator constructs a NodeIterator that iterates over elements in b that
+// are not in a. Returns the iterator, and a pointer to an integer recording the number
+// of nodes seen.
+func NewDifferenceIterator(a, b NodeIterator) (NodeIterator, *int) {
+ a.Next(true)
+ it := &differenceIterator{
+ a: a,
+ b: b,
+ }
+ return it, &it.count
+}
+
+func (it *differenceIterator) Hash() common.Hash {
+ return it.b.Hash()
+}
+
+func (it *differenceIterator) Parent() common.Hash {
+ return it.b.Parent()
+}
+
+func (it *differenceIterator) Leaf() bool {
+ return it.b.Leaf()
+}
+
+func (it *differenceIterator) LeafBlob() []byte {
+ return it.b.LeafBlob()
+}
+
+func (it *differenceIterator) Path() []byte {
+ return it.b.Path()
+}
+
+func (it *differenceIterator) Next(bool) bool {
+ // Invariants:
+ // - We always advance at least one element in b.
+ // - At the start of this function, a's path is lexically greater than b's.
+ if !it.b.Next(true) {
return false
}
- // Otherwise retrieve the current node and resolve leaf accessors
- state := it.stack[len(it.stack)-1]
+ it.count += 1
+
+ if it.eof {
+ // a has reached eof, so we just return all elements from b
+ return true
+ }
+
+ for {
+ apath, bpath := it.a.Path(), it.b.Path()
+ switch bytes.Compare(apath, bpath) {
+ case -1:
+ // b jumped past a; advance a
+ if !it.a.Next(true) {
+ it.eof = true
+ return true
+ }
+ it.count += 1
+ case 1:
+ // b is before a
+ return true
+ case 0:
+ if it.a.Hash() != it.b.Hash() || it.a.Leaf() != it.b.Leaf() {
+ // Keys are identical, but hashes or leaf status differs
+ return true
+ }
+ if it.a.Leaf() && it.b.Leaf() && !bytes.Equal(it.a.LeafBlob(), it.b.LeafBlob()) {
+ // Both are leaf nodes, but with different values
+ return true
+ }
+
+ // a and b are identical; skip this whole subtree if the nodes have hashes
+ hasHash := it.a.Hash() == common.Hash{}
+ if !it.b.Next(hasHash) {
+ return false
+ }
+ it.count += 1
+ if !it.a.Next(hasHash) {
+ it.eof = true
+ return true
+ }
+ it.count += 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)
+func (it *differenceIterator) Error() error {
+ if err := it.a.Error(); err != nil {
+ return err
}
- return true
+ return it.b.Error()
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-23 03:46:23 +0800