ethclient/gethclient: RPC client wrapper for geth-specific API (ether…

…eum#22977)

This commit adds the package gethclient which is similar to the ethclient
and implements some geth specific functionality.

Co-authored-by: Edgar Aroutiounian <edgar.factorial@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>

ethclient/ethclient.go

@@ -284,17 +284,6 @@ func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*
 	return r, err
 }
 
-func toBlockNumArg(number *big.Int) string {
-	if number == nil {
-		return "latest"
-	}
-	pending := big.NewInt(-1)
-	if number.Cmp(pending) == 0 {
-		return "pending"
-	}
-	return hexutil.EncodeBig(number)
-}
-
 type rpcProgress struct {
 	StartingBlock hexutil.Uint64
 	CurrentBlock  hexutil.Uint64
@@ -462,8 +451,6 @@ func (ec *Client) PendingTransactionCount(ctx context.Context) (uint, error) {
 	return uint(num), err
 }
 
-// TODO: SubscribePendingTransactions (needs server side)
-
 // Contract Calling
 
 // CallContract executes a message call transaction, which is directly executed in the VM
@@ -537,6 +524,17 @@ func (ec *Client) SendTransaction(ctx context.Context, tx *types.Transaction) er
 	return ec.c.CallContext(ctx, nil, "eth_sendRawTransaction", hexutil.Encode(data))
 }
 
+func toBlockNumArg(number *big.Int) string {
+	if number == nil {
+		return "latest"
+	}
+	pending := big.NewInt(-1)
+	if number.Cmp(pending) == 0 {
+		return "pending"
+	}
+	return hexutil.EncodeBig(number)
+}
+
 func toCallArg(msg ethereum.CallMsg) interface{} {
 	arg := map[string]interface{}{
 		"from": msg.From,

ethclient/gethclient/gethclient.go

@@ -0,0 +1,235 @@
+// Copyright 2021 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 gethclient provides an RPC client for geth-specific APIs.
+package gethclient
+
+import (
+	"context"
+	"math/big"
+	"runtime"
+	"runtime/debug"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+// Client is a wrapper around rpc.Client that implements geth-specific functionality.
+//
+// If you want to use the standardized Ethereum RPC functionality, use ethclient.Client instead.
+type Client struct {
+	c *rpc.Client
+}
+
+// New creates a client that uses the given RPC client.
+func New(c *rpc.Client) *Client {
+	return &Client{c}
+}
+
+// CreateAccessList tries to create an access list for a specific transaction based on the
+// current pending state of the blockchain.
+func (ec *Client) CreateAccessList(ctx context.Context, msg ethereum.CallMsg) (*types.AccessList, uint64, string, error) {
+	type accessListResult struct {
+		Accesslist *types.AccessList `json:"accessList"`
+		Error      string            `json:"error,omitempty"`
+		GasUsed    hexutil.Uint64    `json:"gasUsed"`
+	}
+	var result accessListResult
+	if err := ec.c.CallContext(ctx, &result, "eth_createAccessList", toCallArg(msg)); err != nil {
+		return nil, 0, "", err
+	}
+	return result.Accesslist, uint64(result.GasUsed), result.Error, nil
+}
+
+// AccountResult is the result of a GetProof operation.
+type AccountResult struct {
+	Address      common.Address  `json:"address"`
+	AccountProof []string        `json:"accountProof"`
+	Balance      *big.Int        `json:"balance"`
+	CodeHash     common.Hash     `json:"codeHash"`
+	Nonce        uint64          `json:"nonce"`
+	StorageHash  common.Hash     `json:"storageHash"`
+	StorageProof []StorageResult `json:"storageProof"`
+}
+
+// StorageResult provides a proof for a key-value pair.
+type StorageResult struct {
+	Key   string   `json:"key"`
+	Value *big.Int `json:"value"`
+	Proof []string `json:"proof"`
+}
+
+// GetProof returns the account and storage values of the specified account including the Merkle-proof.
+// The block number can be nil, in which case the value is taken from the latest known block.
+func (ec *Client) GetProof(ctx context.Context, account common.Address, keys []string, blockNumber *big.Int) (*AccountResult, error) {
+
+	type storageResult struct {
+		Key   string       `json:"key"`
+		Value *hexutil.Big `json:"value"`
+		Proof []string     `json:"proof"`
+	}
+
+	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"`
+	}
+
+	var res accountResult
+	err := ec.c.CallContext(ctx, &res, "eth_getProof", account, keys, toBlockNumArg(blockNumber))
+	// Turn hexutils back to normal datatypes
+	storageResults := make([]StorageResult, 0, len(res.StorageProof))
+	for _, st := range res.StorageProof {
+		storageResults = append(storageResults, StorageResult{
+			Key:   st.Key,
+			Value: st.Value.ToInt(),
+			Proof: st.Proof,
+		})
+	}
+	result := AccountResult{
+		Address:      res.Address,
+		AccountProof: res.AccountProof,
+		Balance:      res.Balance.ToInt(),
+		Nonce:        uint64(res.Nonce),
+		CodeHash:     res.CodeHash,
+		StorageHash:  res.StorageHash,
+	}
+	return &result, err
+}
+
+// OverrideAccount specifies the state of an account to be overridden.
+type OverrideAccount struct {
+	Nonce     uint64                      `json:"nonce"`
+	Code      []byte                      `json:"code"`
+	Balance   *big.Int                    `json:"balance"`
+	State     map[common.Hash]common.Hash `json:"state"`
+	StateDiff map[common.Hash]common.Hash `json:"stateDiff"`
+}
+
+// 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.
+//
+// overrides specifies a map of contract states that should be overwritten before executing
+// the message call.
+// Please use ethclient.CallContract instead if you don't need the override functionality.
+func (ec *Client) CallContract(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int, overrides *map[common.Address]OverrideAccount) ([]byte, error) {
+	var hex hexutil.Bytes
+	err := ec.c.CallContext(
+		ctx, &hex, "eth_call", toCallArg(msg),
+		toBlockNumArg(blockNumber), toOverrideMap(overrides),
+	)
+	return hex, err
+}
+
+// GCStats retrieves the current garbage collection stats from a geth node.
+func (ec *Client) GCStats(ctx context.Context) (*debug.GCStats, error) {
+	var result debug.GCStats
+	err := ec.c.CallContext(ctx, &result, "debug_gcStats")
+	return &result, err
+}
+
+// MemStats retrieves the current memory stats from a geth node.
+func (ec *Client) MemStats(ctx context.Context) (*runtime.MemStats, error) {
+	var result runtime.MemStats
+	err := ec.c.CallContext(ctx, &result, "debug_memStats")
+	return &result, err
+}
+
+// SetHead sets the current head of the local chain by block number.
+// Note, this is a destructive action and may severely damage your chain.
+// Use with extreme caution.
+func (ec *Client) SetHead(ctx context.Context, number *big.Int) error {
+	return ec.c.CallContext(ctx, nil, "debug_setHead", toBlockNumArg(number))
+}
+
+// GetNodeInfo retrieves the node info of a geth node.
+func (ec *Client) GetNodeInfo(ctx context.Context) (*p2p.NodeInfo, error) {
+	var result p2p.NodeInfo
+	err := ec.c.CallContext(ctx, &result, "admin_nodeInfo")
+	return &result, err
+}
+
+// SubscribePendingTransactions subscribes to new pending transactions.
+func (ec *Client) SubscribePendingTransactions(ctx context.Context, ch chan<- common.Hash) (*rpc.ClientSubscription, error) {
+	return ec.c.EthSubscribe(ctx, ch, "newPendingTransactions")
+}
+
+func toBlockNumArg(number *big.Int) string {
+	if number == nil {
+		return "latest"
+	}
+	pending := big.NewInt(-1)
+	if number.Cmp(pending) == 0 {
+		return "pending"
+	}
+	return hexutil.EncodeBig(number)
+}
+
+func toCallArg(msg ethereum.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
+}
+
+func toOverrideMap(overrides *map[common.Address]OverrideAccount) interface{} {
+	if overrides == nil {
+		return nil
+	}
+	type overrideAccount struct {
+		Nonce     hexutil.Uint64              `json:"nonce"`
+		Code      hexutil.Bytes               `json:"code"`
+		Balance   *hexutil.Big                `json:"balance"`
+		State     map[common.Hash]common.Hash `json:"state"`
+		StateDiff map[common.Hash]common.Hash `json:"stateDiff"`
+	}
+	result := make(map[common.Address]overrideAccount)
+	for addr, override := range *overrides {
+		result[addr] = overrideAccount{
+			Nonce:     hexutil.Uint64(override.Nonce),
+			Code:      override.Code,
+			Balance:   (*hexutil.Big)(override.Balance),
+			State:     override.State,
+			StateDiff: override.StateDiff,
+		}
+	}
+	return &result
+}