248 lines
8.7 KiB
Go
248 lines
8.7 KiB
Go
// 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 bind
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"math/big"
|
|
"sync"
|
|
"sync/atomic"
|
|
|
|
"github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/core/types"
|
|
"github.com/ethereum/go-ethereum/rlp"
|
|
"github.com/ethereum/go-ethereum/rpc"
|
|
)
|
|
|
|
// ContractCaller defines the methods needed to allow operating with contract on a read
|
|
// only basis.
|
|
type ContractCaller interface {
|
|
// ContractCall executes an Ethereum contract call with the specified data as
|
|
// the input.
|
|
ContractCall(contract common.Address, data []byte) ([]byte, error)
|
|
}
|
|
|
|
// ContractTransactor defines the methods needed to allow operating with contract
|
|
// on a write only basis. Beside the transacting method, the remainder are helpers
|
|
// used when the user does not provide some needed values, but rather leaves it up
|
|
// to the transactor to decide.
|
|
type ContractTransactor interface {
|
|
// Nonce retrieves the current pending nonce associated with an account.
|
|
AccountNonce(account common.Address) (uint64, error)
|
|
|
|
// GasPrice retrieves the currently suggested gas price to allow a timely execution
|
|
// of a transaction.
|
|
GasPrice() (*big.Int, error)
|
|
|
|
// GasLimit tries to estimate the gas needed to execute a specific transaction.
|
|
GasLimit(sender, contract common.Address, value *big.Int, data []byte) (*big.Int, error)
|
|
|
|
// SendTransaction injects the transaction into the pending pool for execution.
|
|
SendTransaction(*types.Transaction) error
|
|
}
|
|
|
|
// ContractBackend defines the methods needed to allow operating with contract
|
|
// on a read-write basis.
|
|
type ContractBackend interface {
|
|
ContractCaller
|
|
ContractTransactor
|
|
}
|
|
|
|
// nilBackend implements bind.ContractBackend, but panics on any method call.
|
|
// Its sole purpose is to support the binding tests to construct the generated
|
|
// wrappers without calling any methods on them.
|
|
type nilBackend struct{}
|
|
|
|
func (*nilBackend) ContractCall(common.Address, []byte) ([]byte, error) { panic("not implemented") }
|
|
func (*nilBackend) SendTransaction(*types.Transaction) error { panic("not implemented") }
|
|
func (*nilBackend) AccountNonce(common.Address) (uint64, error) { panic("not implemented") }
|
|
func (*nilBackend) GasPrice() (*big.Int, error) { panic("not implemented") }
|
|
func (*nilBackend) GasLimit(common.Address, common.Address, *big.Int, []byte) (*big.Int, error) {
|
|
panic("not implemented")
|
|
}
|
|
|
|
// Helper backend for internal tests. Will panic on any invocation!
|
|
var NilBackend = new(nilBackend)
|
|
|
|
// rpcBackend implements bind.ContractBackend, and acts as the data provider to
|
|
// Ethereum contracts bound to Go structs. It uses an RPC connection to delegate
|
|
// all its functionality.
|
|
//
|
|
// Note: The current implementation is a blocking one. This should be replaced
|
|
// by a proper async version when a real RPC client is created.
|
|
type rpcBackend struct {
|
|
client rpc.Client // RPC client connection to interact with an API server
|
|
autoid uint32 // ID number to use for the next API request
|
|
lock sync.Mutex // Singleton access until we get to request multiplexing
|
|
}
|
|
|
|
// NewRPCBackend creates a new binding backend to an RPC provider that can be
|
|
// used to interact with remote contracts.
|
|
func NewRPCBackend(client rpc.Client) ContractBackend {
|
|
return &rpcBackend{
|
|
client: client,
|
|
}
|
|
}
|
|
|
|
// request is a JSON RPC request package assembled internally from the client
|
|
// method calls.
|
|
type request struct {
|
|
JsonRpc string `json:"jsonrpc"` // Version of the JSON RPC protocol, always set to 2.0
|
|
Id int `json:"id"` // Auto incrementing ID number for this request
|
|
Method string `json:"method"` // Remote procedure name to invoke on the server
|
|
Params []interface{} `json:"params"` // List of parameters to pass through (keep types simple)
|
|
}
|
|
|
|
// response is a JSON RPC response package sent back from the API server.
|
|
type response struct {
|
|
JsonRpc string `json:"jsonrpc"` // Version of the JSON RPC protocol, always set to 2.0
|
|
Id int `json:"id"` // Auto incrementing ID number for this request
|
|
Error json.RawMessage `json:"error"` // Any error returned by the remote side
|
|
Result json.RawMessage `json:"result"` // Whatever the remote side sends us in reply
|
|
}
|
|
|
|
// request forwards an API request to the RPC server, and parses the response.
|
|
//
|
|
// This is currently painfully non-concurrent, but it will have to do until we
|
|
// find the time for niceties like this :P
|
|
func (backend *rpcBackend) request(method string, params []interface{}) (json.RawMessage, error) {
|
|
backend.lock.Lock()
|
|
defer backend.lock.Unlock()
|
|
|
|
// Ugly hack to serialize an empty list properly
|
|
if params == nil {
|
|
params = []interface{}{}
|
|
}
|
|
// Assemble the request object
|
|
req := &request{
|
|
JsonRpc: "2.0",
|
|
Id: int(atomic.AddUint32(&backend.autoid, 1)),
|
|
Method: method,
|
|
Params: params,
|
|
}
|
|
if err := backend.client.Send(req); err != nil {
|
|
return nil, err
|
|
}
|
|
res := new(response)
|
|
if err := backend.client.Recv(res); err != nil {
|
|
return nil, err
|
|
}
|
|
if len(res.Error) > 0 {
|
|
return nil, fmt.Errorf("remote error: %s", string(res.Error))
|
|
}
|
|
return res.Result, nil
|
|
}
|
|
|
|
// ContractCall implements ContractCaller.ContractCall, delegating the execution of
|
|
// a contract call to the remote node, returning the reply to for local processing.
|
|
func (b *rpcBackend) ContractCall(contract common.Address, data []byte) ([]byte, error) {
|
|
// Pack up the request into an RPC argument
|
|
args := struct {
|
|
To common.Address `json:"to"`
|
|
Data string `json:"data"`
|
|
}{
|
|
To: contract,
|
|
Data: common.ToHex(data),
|
|
}
|
|
// Execute the RPC call and retrieve the response
|
|
res, err := b.request("eth_call", []interface{}{args, "pending"})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var hex string
|
|
if err := json.Unmarshal(res, &hex); err != nil {
|
|
return nil, err
|
|
}
|
|
// Convert the response back to a Go byte slice and return
|
|
return common.FromHex(hex), nil
|
|
}
|
|
|
|
// AccountNonce implements ContractTransactor.AccountNonce, delegating the
|
|
// current account nonce retrieval to the remote node.
|
|
func (b *rpcBackend) AccountNonce(account common.Address) (uint64, error) {
|
|
res, err := b.request("eth_getTransactionCount", []interface{}{account.Hex(), "pending"})
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
var hex string
|
|
if err := json.Unmarshal(res, &hex); err != nil {
|
|
return 0, err
|
|
}
|
|
return new(big.Int).SetBytes(common.FromHex(hex)).Uint64(), nil
|
|
}
|
|
|
|
// GasPrice implements ContractTransactor.GasPrice, delegating the gas price
|
|
// oracle request to the remote node.
|
|
func (b *rpcBackend) GasPrice() (*big.Int, error) {
|
|
res, err := b.request("eth_gasPrice", nil)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var hex string
|
|
if err := json.Unmarshal(res, &hex); err != nil {
|
|
return nil, err
|
|
}
|
|
return new(big.Int).SetBytes(common.FromHex(hex)), nil
|
|
}
|
|
|
|
// GasLimit implements ContractTransactor.GasLimit, delegating the gas estimation
|
|
// to the remote node.
|
|
func (b *rpcBackend) GasLimit(sender, contract common.Address, value *big.Int, data []byte) (*big.Int, error) {
|
|
// Pack up the request into an RPC argument
|
|
args := struct {
|
|
From common.Address `json:"from"`
|
|
To common.Address `json:"to"`
|
|
Value *rpc.HexNumber `json:"value"`
|
|
Data string `json:"data"`
|
|
}{
|
|
From: sender,
|
|
To: contract,
|
|
Data: common.ToHex(data),
|
|
Value: rpc.NewHexNumber(value),
|
|
}
|
|
// Execute the RPC call and retrieve the response
|
|
res, err := b.request("eth_estimateGas", []interface{}{args})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var hex string
|
|
if err := json.Unmarshal(res, &hex); err != nil {
|
|
return nil, err
|
|
}
|
|
// Convert the response back to a Go byte slice and return
|
|
return new(big.Int).SetBytes(common.FromHex(hex)), nil
|
|
}
|
|
|
|
// Transact implements ContractTransactor.SendTransaction, delegating the raw
|
|
// transaction injection to the remote node.
|
|
func (b *rpcBackend) SendTransaction(tx *types.Transaction) error {
|
|
data, err := rlp.EncodeToBytes(tx)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
res, err := b.request("eth_sendRawTransaction", []interface{}{common.ToHex(data)})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
var hex string
|
|
if err := json.Unmarshal(res, &hex); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|