Implement eip-1186, eth_getProof

common/bytes.go

@@ -28,6 +28,15 @@ func ToHex(b []byte) string {
 	return "0x" + hex
 }
 
+// ToHexArray creates a array of hex-string based on []byte
+func ToHexArray(b [][]byte) []string {
+	r := make([]string, len(b))
+	for i := range b {
+		r[i] = ToHex(b[i])
+	}
+	return r
+}
+
 func FromHex(s string) []byte {
 	if len(s) > 1 {
 		if s[0:2] == "0x" || s[0:2] == "0X" {

core/state/statedb.go

@@ -18,6 +18,7 @@
 package state
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 	"sort"
@@ -36,6 +37,17 @@ type revision struct {
 	journalIndex int
 }
 
+type proofList [][]byte
+
+func (n *proofList) Put(key []byte, value []byte) error {
+	*n = append(*n, value)
+	return nil
+}
+
+func (n *proofList) Delete(key []byte) error {
+	panic("not supported")
+}
+
 var (
 	// emptyState is the known hash of an empty state trie entry.
 	emptyState = crypto.Keccak256Hash(nil)
@@ -92,6 +104,29 @@ func (self *StateDB) SubRefund(gas uint64) {
 	self.refund -= gas
 }
 
+// GetProof returns the Merkle proof for a given account.
+func (s *StateDB) GetProof(addr common.Address) ([][]byte, error) {
+	return s.GetProofByHash(crypto.Keccak256Hash(addr.Bytes()))
+}
+
+// GetProofByHash returns the Merkle proof for a given account.
+func (s *StateDB) GetProofByHash(addrHash common.Hash) ([][]byte, error) {
+	var proof proofList
+	err := s.trie.Prove(addrHash[:], 0, &proof)
+	return proof, err
+}
+
+// GetStorageProof returns the Merkle proof for given storage slot.
+func (s *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) {
+	var proof proofList
+	trie := s.StorageTrie(a)
+	if trie == nil {
+		return proof, errors.New("storage trie for requested address does not exist")
+	}
+	err := trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof)
+	return proof, err
+}
+
 func (self *StateDB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash {
 	stateObject := self.getStateObject(addr)
 	if stateObject != nil {

eth/api_backend.go

@@ -98,17 +98,20 @@ func (b *EthApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 	return b.eth.blockchain.GetBlockByNumber(uint64(blockNr)), nil
 }
 
-func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
+func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
 	// Pending state is only known by the miner
-	if blockNr == rpc.PendingBlockNumber {
+	if number == rpc.PendingBlockNumber {
 		block, state := b.eth.miner.Pending()
 		return state, block.Header(), nil
 	}
 	// Otherwise resolve the block number and return its state
-	header, err := b.HeaderByNumber(ctx, blockNr)
-	if header == nil || err != nil {
+	header, err := b.HeaderByNumber(ctx, number)
+	if err != nil {
 		return nil, nil, err
 	}
+	if header == nil {
+		return nil, nil, errors.New("header not found")
+	}
 	stateDb, err := b.eth.BlockChain().StateAt(header.Root)
 	return stateDb, header, err
 }

internal/ethapi/api.go

@@ -527,6 +527,72 @@ func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Add
 	return b, state.Error()
 }
 
+// Result structs for GetProof
+type AccountResult struct {
+	Address      common.Address  `json:"address"`
+	AccountProof []string        `json:"accountProof"`
+	Balance      *hexutil.Big    `json:"balance"`
+	CodeHash     common.Hash     `json:"codeHash"`
+	Nonce        hexutil.Uint64  `json:"nonce"`
+	StorageHash  common.Hash     `json:"storageHash"`
+	StorageProof []StorageResult `json:"storageProof"`
+}
+type StorageResult struct {
+	Key   string       `json:"key"`
+	Value *hexutil.Big `json:"value"`
+	Proof []string     `json:"proof"`
+}
+
+// GetProof returns the Merkle-proof for a given account and optionally some storage keys.
+func (s *PublicBlockChainAPI) GetProof(ctx context.Context, address common.Address, storageKeys []string, blockNr rpc.BlockNumber) (*AccountResult, error) {
+	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
+	if state == nil || err != nil {
+		return nil, err
+	}
+
+	storageTrie := state.StorageTrie(address)
+	storageHash := types.EmptyRootHash
+	codeHash := state.GetCodeHash(address)
+	storageProof := make([]StorageResult, len(storageKeys))
+
+	// if we have a storageTrie, (which means the account exists), we can update the storagehash
+	if storageTrie != nil {
+		storageHash = storageTrie.Hash()
+	} else {
+		// no storageTrie means the account does not exist, so the codeHash is the hash of an empty bytearray.
+		codeHash = crypto.Keccak256Hash(nil)
+	}
+
+	// create the proof for the storageKeys
+	for i, key := range storageKeys {
+		if storageTrie != nil {
+			proof, storageError := state.GetStorageProof(address, common.HexToHash(key))
+			if storageError != nil {
+				return nil, storageError
+			}
+			storageProof[i] = StorageResult{key, (*hexutil.Big)(state.GetState(address, common.HexToHash(key)).Big()), common.ToHexArray(proof)}
+		} else {
+			storageProof[i] = StorageResult{key, &hexutil.Big{}, []string{}}
+		}
+	}
+
+	// create the accountProof
+	accountProof, proofErr := state.GetProof(address)
+	if proofErr != nil {
+		return nil, proofErr
+	}
+
+	return &AccountResult{
+		Address:      address,
+		AccountProof: common.ToHexArray(accountProof),
+		Balance:      (*hexutil.Big)(state.GetBalance(address)),
+		CodeHash:     codeHash,
+		Nonce:        hexutil.Uint64(state.GetNonce(address)),
+		StorageHash:  storageHash,
+		StorageProof: storageProof,
+	}, state.Error()
+}
+
 // GetBlockByNumber returns the requested block. When blockNr is -1 the chain head is returned. When fullTx is true all
 // transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
 func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, blockNr rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {