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// 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 (
"errors"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/accounts/abi"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
)
// SignerFn is a signer function callback when a contract requires a method to
// sign the transaction before submission.
type SignerFn func(common.Address, *types.Transaction) (*types.Transaction, error)
// AuthOpts is the authorization data required to create a valid Ethereum transaction.
type AuthOpts struct {
Account common.Address // Ethereum account to send the transaction from
Nonce *big.Int // Nonce to use for the transaction execution (nil = use pending state)
Signer SignerFn // Method to use for signing the transaction (mandatory)
Value *big.Int // Funds to transfer along along the transaction (nil = 0 = no funds)
GasPrice *big.Int // Gas price to use for the transaction execution (nil = gas price oracle)
GasLimit *big.Int // Gas limit to set for the transaction execution (nil = estimate + 10%)
}
// BoundContract is the base wrapper object that reflects a contract on the
// Ethereum network. It contains a collection of methods that are used by the
// higher level contract bindings to operate.
type BoundContract struct {
address common.Address // Deployment address of the contract on the Ethereum blockchain
abi abi.ABI // Reflect based ABI to access the correct Ethereum methods
caller ContractCaller // Read interface to interact with the blockchain
transactor ContractTransactor // Write interface to interact with the blockchain
}
// NewBoundContract creates a low level contract interface through which calls
// and transactions may be made through.
func NewBoundContract(address common.Address, abi abi.ABI, caller ContractCaller, transactor ContractTransactor) *BoundContract {
return &BoundContract{
address: address,
abi: abi,
caller: caller,
transactor: transactor,
}
}
// Call invokes the (constant) contract method with params as input values and
// sets the output to result. The result type might be a single field for simple
// returns, a slice of interfaces for anonymous returns and a struct for named
// returns.
func (c *BoundContract) Call(result interface{}, method string, params ...interface{}) error {
input, err := c.abi.Pack(method, params...)
if err != nil {
return err
}
output, err := c.caller.ContractCall(c.address, input)
if err != nil {
return err
}
return c.abi.Unpack(result, method, output)
}
// Transact invokes the (paid) contract method with params as input values and
// value as the fund transfer to the contract.
func (c *BoundContract) Transact(opts *AuthOpts, method string, params ...interface{}) (*types.Transaction, error) {
input, err := c.abi.Pack(method, params...)
if err != nil {
return nil, err
}
// Ensure a valid value field and resolve the account nonce
value := opts.Value
if value == nil {
value = new(big.Int)
}
nonce := uint64(0)
if opts.Nonce == nil {
nonce, err = c.transactor.AccountNonce(opts.Account)
if err != nil {
return nil, fmt.Errorf("failed to retrieve account nonce: %v", err)
}
} else {
nonce = opts.Nonce.Uint64()
}
// Figure out the gas allowance and gas price values
gasPrice := opts.GasPrice
if gasPrice == nil {
gasPrice, err = c.transactor.GasPrice()
if err != nil {
return nil, fmt.Errorf("failed to suggest gas price: %v", err)
}
}
gasLimit := opts.GasLimit
if gasLimit == nil {
gasLimit, err = c.transactor.GasLimit(opts.Account, c.address, value, input)
if err != nil {
return nil, fmt.Errorf("failed to exstimate gas needed: %v", err)
}
}
// Create the transaction, sign it and schedule it for execution
rawTx := types.NewTransaction(nonce, c.address, value, gasLimit, gasPrice, input)
if opts.Signer == nil {
return nil, errors.New("no signer to authorize the transaction with")
}
signedTx, err := opts.Signer(opts.Account, rawTx)
if err != nil {
return nil, err
}
if err := c.transactor.SendTransaction(signedTx); err != nil {
return nil, err
}
return signedTx, nil
}
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