core: optimise (*Billet).Traverse and (*Trie).Find

(*Billet).Traverse changes:
1. Get rid of the `offset` argument. We can cut `from` and pass just the
part that remains. This implies that node with path matching `from` will
also be included in the result, so additional check needs to be added to
the callback function.
2. Pass `path` and `from` without search prefix. Append prefix to the
result inside the callback.
3. Remove duplicating code.

(*Trie).Find changes:
1. Properly prepare `from` argument for traversing function. It closly
depends on the `path` argument.
This commit is contained in:
Anna Shaleva 2021-10-13 10:22:57 +03:00
parent 43ac4e1517
commit 8e7c76827b
2 changed files with 49 additions and 38 deletions

View file

@ -200,7 +200,7 @@ func (b *Billet) incrementRefAndStore(h util.Uint256, bs []byte) {
// returned from `process` function. It also replaces all HashNodes to their
// "unhashed" counterparts until the stop condition is satisfied.
func (b *Billet) Traverse(process func(pathToNode []byte, node Node, nodeBytes []byte) bool, ignoreStorageErr bool) error {
r, err := b.traverse(b.root, []byte{}, []byte{}, 0, process, ignoreStorageErr)
r, err := b.traverse(b.root, []byte{}, []byte{}, process, ignoreStorageErr)
if err != nil && !errors.Is(err, errStop) {
return err
}
@ -208,7 +208,7 @@ func (b *Billet) Traverse(process func(pathToNode []byte, node Node, nodeBytes [
return nil
}
func (b *Billet) traverse(curr Node, path, from []byte, offset int, process func(pathToNode []byte, node Node, nodeBytes []byte) bool, ignoreStorageErr bool) (Node, error) {
func (b *Billet) traverse(curr Node, path, from []byte, process func(pathToNode []byte, node Node, nodeBytes []byte) bool, ignoreStorageErr bool) (Node, error) {
if _, ok := curr.(EmptyNode); ok {
// We're not interested in EmptyNodes, and they do not affect the
// traversal process, thus remain them untouched.
@ -222,9 +222,9 @@ func (b *Billet) traverse(curr Node, path, from []byte, offset int, process func
}
return nil, err
}
return b.traverse(r, path, from, offset, process, ignoreStorageErr)
return b.traverse(r, path, from, process, ignoreStorageErr)
}
if _, ok := curr.(*LeafNode); !ok || len(from) <= offset && (len(from) == 0 || !bytes.Equal(path, from)) {
if len(from) == 0 {
bytes := slice.Copy(curr.Bytes())
if process(fromNibbles(path), curr, bytes) {
return curr, errStop
@ -234,33 +234,25 @@ func (b *Billet) traverse(curr Node, path, from []byte, offset int, process func
case *LeafNode:
return b.tryCollapseLeaf(n), nil
case *BranchNode:
if len(from) > offset {
startIndex := from[offset]
for i := startIndex; i < lastChild; i++ {
newOffset := len(from)
if i == startIndex {
newOffset = offset + 1
var (
startIndex byte
endIndex byte = childrenCount
)
if len(from) != 0 {
endIndex = lastChild
startIndex, from = splitPath(from)
}
r, err := b.traverse(n.Children[i], append(path, i), from, newOffset, process, ignoreStorageErr)
if err != nil {
if !errors.Is(err, errStop) {
return nil, err
}
n.Children[i] = r
return n, err
}
n.Children[i] = r
}
return b.tryCollapseBranch(n), nil
}
for i, child := range n.Children {
for i := startIndex; i < endIndex; i++ {
var newPath []byte
if i == lastChild {
newPath = path
} else {
newPath = append(path, byte(i))
newPath = append(path, i)
}
r, err := b.traverse(child, newPath, from, offset, process, ignoreStorageErr)
if i != startIndex {
from = []byte{}
}
r, err := b.traverse(n.Children[i], newPath, from, process, ignoreStorageErr)
if err != nil {
if !errors.Is(err, errStop) {
return nil, err
@ -272,15 +264,14 @@ func (b *Billet) traverse(curr Node, path, from []byte, offset int, process func
}
return b.tryCollapseBranch(n), nil
case *ExtensionNode:
var newOffset int
if len(from) > offset && bytes.HasPrefix(from[offset:], n.key) {
newOffset = offset + len(n.key)
} else if len(from) <= offset || bytes.Compare(n.key, from[offset:]) > 0 {
newOffset = len(from)
if len(from) != 0 && bytes.HasPrefix(from, n.key) {
from = from[len(n.key):]
} else if len(from) == 0 || bytes.Compare(n.key, from) > 0 {
from = []byte{}
} else {
return b.tryCollapseExtension(n), nil
}
r, err := b.traverse(n.next, append(path, n.key...), from, newOffset, process, ignoreStorageErr)
r, err := b.traverse(n.next, append(path, n.key...), from, process, ignoreStorageErr)
if err != nil && !errors.Is(err, errStop) {
return nil, err
}

View file

@ -541,12 +541,29 @@ func (t *Trie) Find(prefix, from []byte, max int) ([]storage.KeyValue, error) {
if !bytes.HasPrefix(from, prefix) {
return nil, errors.New("`from` argument doesn't match specified prefix")
}
fromP = toNibbles(from)
fromP = toNibbles(from)[len(prefixP):]
}
_, start, path, err := t.getWithPath(t.root, prefixP, false)
if err != nil {
return nil, fmt.Errorf("failed to determine the start node: %w", err)
}
path = path[len(prefixP):]
if len(fromP) > 0 {
if len(path) <= len(fromP) && bytes.HasPrefix(fromP, path) {
fromP = fromP[len(path):]
} else if len(path) > len(fromP) && bytes.HasPrefix(path, fromP) {
fromP = []byte{}
} else {
cmp := bytes.Compare(path, fromP)
switch {
case cmp < 0:
return []storage.KeyValue{}, nil
case cmp > 0:
fromP = []byte{}
}
}
}
var (
res []storage.KeyValue
@ -555,15 +572,18 @@ func (t *Trie) Find(prefix, from []byte, max int) ([]storage.KeyValue, error) {
b := NewBillet(t.root.Hash(), false, t.Store)
process := func(pathToNode []byte, node Node, _ []byte) bool {
if leaf, ok := node.(*LeafNode); ok {
key := append(prefix, pathToNode...)
if !bytes.Equal(key, from) { // (*Billet).traverse includes `from` path into result if so. Need to filter out manually.
res = append(res, storage.KeyValue{
Key: pathToNode,
Key: key,
Value: slice.Copy(leaf.value),
})
count++
}
}
return count >= max
}
_, err = b.traverse(start, path, fromP, len(path), process, false)
_, err = b.traverse(start, path, fromP, process, false)
if err != nil && !errors.Is(err, errStop) {
return nil, err
}