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authoraaronbuchwald <[email protected]>2020-11-30 12:22:29 -0500
committerGitHub <[email protected]>2020-11-30 12:22:29 -0500
commitcfc11729d0f24b8e42a3f9cbcf7534e2db09d720 (patch)
tree9478961d310c5b69ca65fc9551ef9976b1d01da5 /ethclient
parentae4541f42a666fb5ae1c36d6f7423c3d9eb2c875 (diff)
parent415b1eb564efc70cf7e673358286e19de8551fbf (diff)
Merge pull request #62 from ava-labs/devv0.3.15
Dev
Diffstat (limited to 'ethclient')
-rw-r--r--ethclient/ethclient.go586
-rw-r--r--ethclient/signer.go59
2 files changed, 645 insertions, 0 deletions
diff --git a/ethclient/ethclient.go b/ethclient/ethclient.go
new file mode 100644
index 0000000..6dd4df8
--- /dev/null
+++ b/ethclient/ethclient.go
@@ -0,0 +1,586 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package ethclient provides a client for the Ethereum RPC API.
+package ethclient
+
+import (
+ "context"
+ "encoding/json"
+ "errors"
+ "fmt"
+ "math/big"
+
+ "github.com/ava-labs/avalanchego/ids"
+ "github.com/ava-labs/coreth"
+ "github.com/ava-labs/coreth/core/types"
+ "github.com/ava-labs/coreth/rpc"
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/common/hexutil"
+ "github.com/ethereum/go-ethereum/rlp"
+)
+
+// Client defines typed wrappers for the Ethereum RPC API.
+type Client struct {
+ c *rpc.Client
+}
+
+// Dial connects a client to the given URL.
+func Dial(rawurl string) (*Client, error) {
+ return DialContext(context.Background(), rawurl)
+}
+
+func DialContext(ctx context.Context, rawurl string) (*Client, error) {
+ c, err := rpc.DialContext(ctx, rawurl)
+ if err != nil {
+ return nil, err
+ }
+ return NewClient(c), nil
+}
+
+// NewClient creates a client that uses the given RPC client.
+func NewClient(c *rpc.Client) *Client {
+ return &Client{c}
+}
+
+func (ec *Client) Close() {
+ ec.c.Close()
+}
+
+// Blockchain Access
+
+// ChainId retrieves the current chain ID for transaction replay protection.
+func (ec *Client) ChainID(ctx context.Context) (*big.Int, error) {
+ var result hexutil.Big
+ err := ec.c.CallContext(ctx, &result, "eth_chainId")
+ if err != nil {
+ return nil, err
+ }
+ return (*big.Int)(&result), err
+}
+
+// BlockByHash returns the given full block.
+//
+// Note that loading full blocks requires two requests. Use HeaderByHash
+// if you don't need all transactions or uncle headers.
+func (ec *Client) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
+ return ec.getBlock(ctx, "eth_getBlockByHash", hash, true)
+}
+
+// BlockByNumber returns a block from the current canonical chain. If number is nil, the
+// latest known block is returned.
+//
+// Note that loading full blocks requires two requests. Use HeaderByNumber
+// if you don't need all transactions or uncle headers.
+func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
+ return ec.getBlock(ctx, "eth_getBlockByNumber", toBlockNumArg(number), true)
+}
+
+// BlockNumber returns the most recent block number
+func (ec *Client) BlockNumber(ctx context.Context) (uint64, error) {
+ var result hexutil.Uint64
+ err := ec.c.CallContext(ctx, &result, "eth_blockNumber")
+ return uint64(result), err
+}
+
+type rpcBlock struct {
+ Hash common.Hash `json:"hash"`
+ Transactions []rpcTransaction `json:"transactions"`
+ UncleHashes []common.Hash `json:"uncles"`
+ Version uint32 `json:"version"`
+ BlockExtraData string `json:"blockExtraData"`
+}
+
+func (ec *Client) getBlock(ctx context.Context, method string, args ...interface{}) (*types.Block, error) {
+ var raw json.RawMessage
+ err := ec.c.CallContext(ctx, &raw, method, args...)
+ if err != nil {
+ return nil, err
+ } else if len(raw) == 0 {
+ return nil, coreth.NotFound
+ }
+ // Decode header and transactions.
+ var head *types.Header
+ var body rpcBlock
+ if err := json.Unmarshal(raw, &head); err != nil {
+ return nil, err
+ }
+ if err := json.Unmarshal(raw, &body); err != nil {
+ return nil, err
+ }
+
+ var blockExtraData *[]byte
+ if len(body.BlockExtraData) != 0 {
+ blockExtraDataDecoded, err := hexutil.Decode(body.BlockExtraData)
+ if err != nil {
+ return nil, fmt.Errorf("problem parsing block extra data: %w", err)
+ }
+ blockExtraData = &blockExtraDataDecoded
+ }
+
+ // Quick-verify transaction and uncle lists. This mostly helps with debugging the server.
+ if head.UncleHash == types.EmptyUncleHash && len(body.UncleHashes) > 0 {
+ return nil, fmt.Errorf("server returned non-empty uncle list but block header indicates no uncles")
+ }
+ if head.UncleHash != types.EmptyUncleHash && len(body.UncleHashes) == 0 {
+ return nil, fmt.Errorf("server returned empty uncle list but block header indicates uncles")
+ }
+ if head.TxHash == types.EmptyRootHash && len(body.Transactions) > 0 {
+ return nil, fmt.Errorf("server returned non-empty transaction list but block header indicates no transactions")
+ }
+ if head.TxHash != types.EmptyRootHash && len(body.Transactions) == 0 {
+ return nil, fmt.Errorf("server returned empty transaction list but block header indicates transactions")
+ }
+ // Load uncles because they are not included in the block response.
+ var uncles []*types.Header
+ if len(body.UncleHashes) > 0 {
+ uncles = make([]*types.Header, len(body.UncleHashes))
+ reqs := make([]rpc.BatchElem, len(body.UncleHashes))
+ for i := range reqs {
+ reqs[i] = rpc.BatchElem{
+ Method: "eth_getUncleByBlockHashAndIndex",
+ Args: []interface{}{body.Hash, hexutil.EncodeUint64(uint64(i))},
+ Result: &uncles[i],
+ }
+ }
+ if err := ec.c.BatchCallContext(ctx, reqs); err != nil {
+ return nil, err
+ }
+ for i := range reqs {
+ if reqs[i].Error != nil {
+ return nil, reqs[i].Error
+ }
+ if uncles[i] == nil {
+ return nil, fmt.Errorf("got null header for uncle %d of block %x", i, body.Hash[:])
+ }
+ }
+ }
+ // Fill the sender cache of transactions in the block.
+ txs := make([]*types.Transaction, len(body.Transactions))
+ for i, tx := range body.Transactions {
+ if tx.From != nil {
+ setSenderFromServer(tx.tx, *tx.From, body.Hash)
+ }
+ txs[i] = tx.tx
+ }
+ return types.NewBlockWithHeader(head).WithBody(txs, uncles, body.Version, blockExtraData), nil
+}
+
+// HeaderByHash returns the block header with the given hash.
+func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
+ var head *types.Header
+ err := ec.c.CallContext(ctx, &head, "eth_getBlockByHash", hash, false)
+ if err == nil && head == nil {
+ err = coreth.NotFound
+ }
+ return head, err
+}
+
+// HeaderByNumber returns a block header from the current canonical chain. If number is
+// nil, the latest known header is returned.
+func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error) {
+ var head *types.Header
+ err := ec.c.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(number), false)
+ if err == nil && head == nil {
+ err = coreth.NotFound
+ }
+ return head, err
+}
+
+type rpcTransaction struct {
+ tx *types.Transaction
+ txExtraInfo
+}
+
+type txExtraInfo struct {
+ BlockNumber *string `json:"blockNumber,omitempty"`
+ BlockHash *common.Hash `json:"blockHash,omitempty"`
+ From *common.Address `json:"from,omitempty"`
+}
+
+func (tx *rpcTransaction) UnmarshalJSON(msg []byte) error {
+ if err := json.Unmarshal(msg, &tx.tx); err != nil {
+ return err
+ }
+ return json.Unmarshal(msg, &tx.txExtraInfo)
+}
+
+// TransactionByHash returns the transaction with the given hash.
+func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (tx *types.Transaction, isPending bool, err error) {
+ var json *rpcTransaction
+ err = ec.c.CallContext(ctx, &json, "eth_getTransactionByHash", hash)
+ if err != nil {
+ return nil, false, err
+ } else if json == nil {
+ return nil, false, coreth.NotFound
+ } else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
+ return nil, false, fmt.Errorf("server returned transaction without signature")
+ }
+ if json.From != nil && json.BlockHash != nil {
+ setSenderFromServer(json.tx, *json.From, *json.BlockHash)
+ }
+ return json.tx, json.BlockNumber == nil, nil
+}
+
+// TransactionSender returns the sender address of the given transaction. The transaction
+// must be known to the remote node and included in the blockchain at the given block and
+// index. The sender is the one derived by the protocol at the time of inclusion.
+//
+// There is a fast-path for transactions retrieved by TransactionByHash and
+// TransactionInBlock. Getting their sender address can be done without an RPC interaction.
+func (ec *Client) TransactionSender(ctx context.Context, tx *types.Transaction, block common.Hash, index uint) (common.Address, error) {
+ // Try to load the address from the cache.
+ sender, err := types.Sender(&senderFromServer{blockhash: block}, tx)
+ if err == nil {
+ return sender, nil
+ }
+ var meta struct {
+ Hash common.Hash
+ From common.Address
+ }
+ if err = ec.c.CallContext(ctx, &meta, "eth_getTransactionByBlockHashAndIndex", block, hexutil.Uint64(index)); err != nil {
+ return common.Address{}, err
+ }
+ if meta.Hash == (common.Hash{}) || meta.Hash != tx.Hash() {
+ return common.Address{}, errors.New("wrong inclusion block/index")
+ }
+ return meta.From, nil
+}
+
+// TransactionCount returns the total number of transactions in the given block.
+func (ec *Client) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
+ var num hexutil.Uint
+ err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByHash", blockHash)
+ return uint(num), err
+}
+
+// TransactionInBlock returns a single transaction at index in the given block.
+func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
+ var json *rpcTransaction
+ err := ec.c.CallContext(ctx, &json, "eth_getTransactionByBlockHashAndIndex", blockHash, hexutil.Uint64(index))
+ if err != nil {
+ return nil, err
+ }
+ if json == nil {
+ return nil, coreth.NotFound
+ } else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
+ return nil, fmt.Errorf("server returned transaction without signature")
+ }
+ if json.From != nil && json.BlockHash != nil {
+ setSenderFromServer(json.tx, *json.From, *json.BlockHash)
+ }
+ return json.tx, err
+}
+
+// TransactionReceipt returns the receipt of a transaction by transaction hash.
+// Note that the receipt is not available for pending transactions.
+func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
+ var r *types.Receipt
+ err := ec.c.CallContext(ctx, &r, "eth_getTransactionReceipt", txHash)
+ if err == nil {
+ if r == nil {
+ return nil, coreth.NotFound
+ }
+ }
+ return r, err
+}
+
+func toBlockNumArg(number *big.Int) string {
+ // The Ethereum implementation uses a different mapping from
+ // negative numbers to special strings (latest, pending) then is
+ // used on its server side. See rpc/types.go for the comparison.
+ // if number == nil {
+ // return "latest"
+ // }
+ // pending := big.NewInt(-1)
+ // if number.Cmp(pending) == 0 {
+ // return "pending"
+ // }
+
+ // In Coreth, latest, pending, and accepted are all treated the same
+ // therefore, if [number] is nil or a negative number in [-3, -1]
+ // we want the latest accepted block
+ if number == nil {
+ return "latest"
+ }
+ low := big.NewInt(-3)
+ high := big.NewInt(-1)
+ if number.Cmp(low) >= 0 && number.Cmp(high) <= 0 {
+ return "latest"
+ }
+ return hexutil.EncodeBig(number)
+}
+
+type rpcProgress struct {
+ StartingBlock hexutil.Uint64
+ CurrentBlock hexutil.Uint64
+ HighestBlock hexutil.Uint64
+ PulledStates hexutil.Uint64
+ KnownStates hexutil.Uint64
+}
+
+// SyncProgress retrieves the current progress of the sync algorithm. If there's
+// no sync currently running, it returns nil.
+// eth_syncing is not implemented in Coreth
+// func (ec *Client) SyncProgress(ctx context.Context) (*coreth.SyncProgress, error) {
+// var raw json.RawMessage
+// if err := ec.c.CallContext(ctx, &raw, "eth_syncing"); err != nil {
+// return nil, err
+// }
+// // Handle the possible response types
+// var syncing bool
+// if err := json.Unmarshal(raw, &syncing); err == nil {
+// return nil, nil // Not syncing (always false)
+// }
+// var progress *rpcProgress
+// if err := json.Unmarshal(raw, &progress); err != nil {
+// return nil, err
+// }
+// return &coreth.SyncProgress{
+// StartingBlock: uint64(progress.StartingBlock),
+// CurrentBlock: uint64(progress.CurrentBlock),
+// HighestBlock: uint64(progress.HighestBlock),
+// PulledStates: uint64(progress.PulledStates),
+// KnownStates: uint64(progress.KnownStates),
+// }, nil
+// }
+
+// SubscribeNewHead subscribes to notifications about the current blockchain head
+// on the given channel.
+func (ec *Client) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (coreth.Subscription, error) {
+ return ec.c.EthSubscribe(ctx, ch, "newHeads")
+}
+
+// State Access
+
+// NetworkID returns the network ID (also known as the chain ID) for this chain.
+func (ec *Client) NetworkID(ctx context.Context) (*big.Int, error) {
+ version := new(big.Int)
+ var ver string
+ if err := ec.c.CallContext(ctx, &ver, "net_version"); err != nil {
+ return nil, err
+ }
+ if _, ok := version.SetString(ver, 10); !ok {
+ return nil, fmt.Errorf("invalid net_version result %q", ver)
+ }
+ return version, nil
+}
+
+// BalanceAt returns the wei balance of the given account.
+// The block number can be nil, in which case the balance is taken from the latest known block.
+func (ec *Client) BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
+ var result hexutil.Big
+ err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, toBlockNumArg(blockNumber))
+ return (*big.Int)(&result), err
+}
+
+// AssetBalanceAt returns the [assetID] balance of the given account
+// The block number can be nil, in which case the balance is taken from the latest known block.
+func (ec *Client) AssetBalanceAt(ctx context.Context, account common.Address, assetID ids.ID, blockNumber *big.Int) (*big.Int, error) {
+ var result hexutil.Big
+ err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, toBlockNumArg(blockNumber), assetID)
+ return (*big.Int)(&result), err
+}
+
+// StorageAt returns the value of key in the contract storage of the given account.
+// The block number can be nil, in which case the value is taken from the latest known block.
+func (ec *Client) StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
+ var result hexutil.Bytes
+ err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, toBlockNumArg(blockNumber))
+ return result, err
+}
+
+// CodeAt returns the contract code of the given account.
+// The block number can be nil, in which case the code is taken from the latest known block.
+func (ec *Client) CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error) {
+ var result hexutil.Bytes
+ err := ec.c.CallContext(ctx, &result, "eth_getCode", account, toBlockNumArg(blockNumber))
+ return result, err
+}
+
+// NonceAt returns the account nonce of the given account.
+// The block number can be nil, in which case the nonce is taken from the latest known block.
+func (ec *Client) NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error) {
+ var result hexutil.Uint64
+ err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, toBlockNumArg(blockNumber))
+ return uint64(result), err
+}
+
+// Filters
+
+// FilterLogs executes a filter query.
+func (ec *Client) FilterLogs(ctx context.Context, q coreth.FilterQuery) ([]types.Log, error) {
+ var result []types.Log
+ arg, err := toFilterArg(q)
+ if err != nil {
+ return nil, err
+ }
+ err = ec.c.CallContext(ctx, &result, "eth_getLogs", arg)
+ return result, err
+}
+
+// SubscribeFilterLogs subscribes to the results of a streaming filter query.
+func (ec *Client) SubscribeFilterLogs(ctx context.Context, q coreth.FilterQuery, ch chan<- types.Log) (coreth.Subscription, error) {
+ arg, err := toFilterArg(q)
+ if err != nil {
+ return nil, err
+ }
+ return ec.c.EthSubscribe(ctx, ch, "logs", arg)
+}
+
+func toFilterArg(q coreth.FilterQuery) (interface{}, error) {
+ arg := map[string]interface{}{
+ "address": q.Addresses,
+ "topics": q.Topics,
+ }
+ if q.BlockHash != nil {
+ arg["blockHash"] = *q.BlockHash
+ if q.FromBlock != nil || q.ToBlock != nil {
+ return nil, fmt.Errorf("cannot specify both BlockHash and FromBlock/ToBlock")
+ }
+ } else {
+ if q.FromBlock == nil {
+ arg["fromBlock"] = "0x0"
+ } else {
+ arg["fromBlock"] = toBlockNumArg(q.FromBlock)
+ }
+ arg["toBlock"] = toBlockNumArg(q.ToBlock)
+ }
+ return arg, nil
+}
+
+// Pending State is irrelevant in Coreth
+
+// // PendingBalanceAt returns the wei balance of the given account in the pending state.
+// func (ec *Client) PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error) {
+// var result hexutil.Big
+// err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, "pending")
+// return (*big.Int)(&result), err
+// }
+
+// // PendingStorageAt returns the value of key in the contract storage of the given account in the pending state.
+// func (ec *Client) PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error) {
+// var result hexutil.Bytes
+// err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, "pending")
+// return result, err
+// }
+
+// // PendingCodeAt returns the contract code of the given account in the pending state.
+// func (ec *Client) PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error) {
+// var result hexutil.Bytes
+// err := ec.c.CallContext(ctx, &result, "eth_getCode", account, "pending")
+// return result, err
+// }
+
+// // PendingNonceAt returns the account nonce of the given account in the pending state.
+// // This is the nonce that should be used for the next transaction.
+// func (ec *Client) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
+// var result hexutil.Uint64
+// err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, "pending")
+// return uint64(result), err
+// }
+
+// // PendingTransactionCount returns the total number of transactions in the pending state.
+// func (ec *Client) PendingTransactionCount(ctx context.Context) (uint, error) {
+// var num hexutil.Uint
+// err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByNumber", "pending")
+// return uint(num), err
+// }
+
+// TODO: SubscribePendingTransactions (needs server side)
+
+// Contract Calling
+
+// CallContract executes a message call transaction, which is directly executed in the VM
+// of the node, but never mined into the blockchain.
+//
+// blockNumber selects the block height at which the call runs. It can be nil, in which
+// case the code is taken from the latest known block. Note that state from very old
+// blocks might not be available.
+func (ec *Client) CallContract(ctx context.Context, msg coreth.CallMsg, blockNumber *big.Int) ([]byte, error) {
+ var hex hexutil.Bytes
+ err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), toBlockNumArg(blockNumber))
+ if err != nil {
+ return nil, err
+ }
+ return hex, nil
+}
+
+// // PendingCallContract executes a message call transaction using the EVM.
+// // The state seen by the contract call is the pending state.
+// func (ec *Client) PendingCallContract(ctx context.Context, msg coreth.CallMsg) ([]byte, error) {
+// var hex hexutil.Bytes
+// err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), "pending")
+// if err != nil {
+// return nil, err
+// }
+// return hex, nil
+// }
+
+// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
+// execution of a transaction.
+func (ec *Client) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
+ var hex hexutil.Big
+ if err := ec.c.CallContext(ctx, &hex, "eth_gasPrice"); err != nil {
+ return nil, err
+ }
+ return (*big.Int)(&hex), nil
+}
+
+// EstimateGas tries to estimate the gas needed to execute a specific transaction based on
+// the current pending state of the backend blockchain. There is no guarantee that this is
+// the true gas limit requirement as other transactions may be added or removed by miners,
+// but it should provide a basis for setting a reasonable default.
+func (ec *Client) EstimateGas(ctx context.Context, msg coreth.CallMsg) (uint64, error) {
+ var hex hexutil.Uint64
+ err := ec.c.CallContext(ctx, &hex, "eth_estimateGas", toCallArg(msg))
+ if err != nil {
+ return 0, err
+ }
+ return uint64(hex), nil
+}
+
+// SendTransaction injects a signed transaction into the pending pool for execution.
+//
+// If the transaction was a contract creation use the TransactionReceipt method to get the
+// contract address after the transaction has been mined.
+func (ec *Client) SendTransaction(ctx context.Context, tx *types.Transaction) error {
+ data, err := rlp.EncodeToBytes(tx)
+ if err != nil {
+ return err
+ }
+ return ec.c.CallContext(ctx, nil, "eth_sendRawTransaction", hexutil.Encode(data))
+}
+
+func toCallArg(msg coreth.CallMsg) interface{} {
+ arg := map[string]interface{}{
+ "from": msg.From,
+ "to": msg.To,
+ }
+ if len(msg.Data) > 0 {
+ arg["data"] = hexutil.Bytes(msg.Data)
+ }
+ if msg.Value != nil {
+ arg["value"] = (*hexutil.Big)(msg.Value)
+ }
+ if msg.Gas != 0 {
+ arg["gas"] = hexutil.Uint64(msg.Gas)
+ }
+ if msg.GasPrice != nil {
+ arg["gasPrice"] = (*hexutil.Big)(msg.GasPrice)
+ }
+ return arg
+}
diff --git a/ethclient/signer.go b/ethclient/signer.go
new file mode 100644
index 0000000..4a9f645
--- /dev/null
+++ b/ethclient/signer.go
@@ -0,0 +1,59 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package ethclient
+
+import (
+ "errors"
+ "math/big"
+
+ "github.com/ava-labs/coreth/core/types"
+ "github.com/ethereum/go-ethereum/common"
+)
+
+// senderFromServer is a types.Signer that remembers the sender address returned by the RPC
+// server. It is stored in the transaction's sender address cache to avoid an additional
+// request in TransactionSender.
+type senderFromServer struct {
+ addr common.Address
+ blockhash common.Hash
+}
+
+var errNotCached = errors.New("sender not cached")
+
+func setSenderFromServer(tx *types.Transaction, addr common.Address, block common.Hash) {
+ // Use types.Sender for side-effect to store our signer into the cache.
+ types.Sender(&senderFromServer{addr, block}, tx)
+}
+
+func (s *senderFromServer) Equal(other types.Signer) bool {
+ os, ok := other.(*senderFromServer)
+ return ok && os.blockhash == s.blockhash
+}
+
+func (s *senderFromServer) Sender(tx *types.Transaction) (common.Address, error) {
+ if s.blockhash == (common.Hash{}) {
+ return common.Address{}, errNotCached
+ }
+ return s.addr, nil
+}
+
+func (s *senderFromServer) Hash(tx *types.Transaction) common.Hash {
+ panic("can't sign with senderFromServer")
+}
+func (s *senderFromServer) SignatureValues(tx *types.Transaction, sig []byte) (R, S, V *big.Int, err error) {
+ panic("can't sign with senderFromServer")
+}