forked from TrueCloudLab/neoneo-go
9d2ef775cf
They never return errors, so their interface should reflect that. This allows to remove quite a lot of useless and never tested code. Notice that Get still does return an error. It can be made not to do that, but usually we need to differentiate between successful/unsuccessful accesses anyway, so this doesn't help much.
79 lines
2.1 KiB
Go
79 lines
2.1 KiB
Go
package mpt
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import (
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"bytes"
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"errors"
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"github.com/nspcc-dev/neo-go/pkg/core/storage"
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"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/util/slice"
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)
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// GetProof returns a proof that key belongs to t.
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// Proof consist of serialized nodes occurring on path from the root to the leaf of key.
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func (t *Trie) GetProof(key []byte) ([][]byte, error) {
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var proof [][]byte
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if len(key) > MaxKeyLength {
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return nil, errors.New("key is too big")
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}
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path := toNibbles(key)
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r, err := t.getProof(t.root, path, &proof)
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if err != nil {
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return proof, err
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}
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t.root = r
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return proof, nil
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}
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func (t *Trie) getProof(curr Node, path []byte, proofs *[][]byte) (Node, error) {
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switch n := curr.(type) {
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case *LeafNode:
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if len(path) == 0 {
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*proofs = append(*proofs, slice.Copy(n.Bytes()))
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return n, nil
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}
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case *BranchNode:
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*proofs = append(*proofs, slice.Copy(n.Bytes()))
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i, path := splitPath(path)
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r, err := t.getProof(n.Children[i], path, proofs)
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if err != nil {
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return nil, err
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}
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n.Children[i] = r
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return n, nil
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case *ExtensionNode:
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if bytes.HasPrefix(path, n.key) {
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*proofs = append(*proofs, slice.Copy(n.Bytes()))
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r, err := t.getProof(n.next, path[len(n.key):], proofs)
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if err != nil {
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return nil, err
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}
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n.next = r
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return n, nil
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}
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case *HashNode:
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r, err := t.getFromStore(n.Hash())
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if err != nil {
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return nil, err
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}
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return t.getProof(r, path, proofs)
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}
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return nil, ErrNotFound
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}
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// VerifyProof verifies that path indeed belongs to a MPT with the specified root hash.
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// It also returns value for the key.
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func VerifyProof(rh util.Uint256, key []byte, proofs [][]byte) ([]byte, bool) {
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path := toNibbles(key)
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tr := NewTrie(NewHashNode(rh), ModeAll, storage.NewMemCachedStore(storage.NewMemoryStore()))
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for i := range proofs {
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h := hash.DoubleSha256(proofs[i])
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tr.Store.Put(makeStorageKey(h), proofs[i])
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}
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_, leaf, _, err := tr.getWithPath(tr.root, path, true)
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if err != nil {
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return nil, false
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}
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return slice.Copy(leaf.(*LeafNode).value), true
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}
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