351 lines
12 KiB
Go
351 lines
12 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package bind
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import (
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"context"
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"errors"
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"fmt"
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"math/big"
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"github.com/ethereum/go-ethereum"
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"github.com/ethereum/go-ethereum/accounts/abi"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/event"
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)
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// SignerFn is a signer function callback when a contract requires a method to
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// sign the transaction before submission.
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type SignerFn func(types.Signer, common.Address, *types.Transaction) (*types.Transaction, error)
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// CallOpts is the collection of options to fine tune a contract call request.
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type CallOpts struct {
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Pending bool // Whether to operate on the pending state or the last known one
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From common.Address // Optional the sender address, otherwise the first account is used
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BlockNumber *big.Int // Optional the block number on which the call should be performed
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Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
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}
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// TransactOpts is the collection of authorization data required to create a
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// valid Ethereum transaction.
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type TransactOpts struct {
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From common.Address // Ethereum account to send the transaction from
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Nonce *big.Int // Nonce to use for the transaction execution (nil = use pending state)
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Signer SignerFn // Method to use for signing the transaction (mandatory)
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Value *big.Int // Funds to transfer along along the transaction (nil = 0 = no funds)
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GasPrice *big.Int // Gas price to use for the transaction execution (nil = gas price oracle)
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GasLimit uint64 // Gas limit to set for the transaction execution (0 = estimate)
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Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
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}
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// FilterOpts is the collection of options to fine tune filtering for events
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// within a bound contract.
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type FilterOpts struct {
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Start uint64 // Start of the queried range
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End *uint64 // End of the range (nil = latest)
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Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
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}
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// WatchOpts is the collection of options to fine tune subscribing for events
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// within a bound contract.
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type WatchOpts struct {
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Start *uint64 // Start of the queried range (nil = latest)
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Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
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}
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// BoundContract is the base wrapper object that reflects a contract on the
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// Ethereum network. It contains a collection of methods that are used by the
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// higher level contract bindings to operate.
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type BoundContract struct {
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address common.Address // Deployment address of the contract on the Ethereum blockchain
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abi abi.ABI // Reflect based ABI to access the correct Ethereum methods
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caller ContractCaller // Read interface to interact with the blockchain
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transactor ContractTransactor // Write interface to interact with the blockchain
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filterer ContractFilterer // Event filtering to interact with the blockchain
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}
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// NewBoundContract creates a low level contract interface through which calls
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// and transactions may be made through.
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func NewBoundContract(address common.Address, abi abi.ABI, caller ContractCaller, transactor ContractTransactor, filterer ContractFilterer) *BoundContract {
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return &BoundContract{
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address: address,
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abi: abi,
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caller: caller,
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transactor: transactor,
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filterer: filterer,
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}
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}
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// DeployContract deploys a contract onto the Ethereum blockchain and binds the
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// deployment address with a Go wrapper.
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func DeployContract(opts *TransactOpts, abi abi.ABI, bytecode []byte, backend ContractBackend, params ...interface{}) (common.Address, *types.Transaction, *BoundContract, error) {
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// Otherwise try to deploy the contract
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c := NewBoundContract(common.Address{}, abi, backend, backend, backend)
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input, err := c.abi.Pack("", params...)
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if err != nil {
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return common.Address{}, nil, nil, err
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}
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tx, err := c.transact(opts, nil, append(bytecode, input...))
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if err != nil {
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return common.Address{}, nil, nil, err
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}
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c.address = crypto.CreateAddress(opts.From, tx.Nonce())
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return c.address, tx, c, nil
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}
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// Call invokes the (constant) contract method with params as input values and
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// sets the output to result. The result type might be a single field for simple
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// returns, a slice of interfaces for anonymous returns and a struct for named
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// returns.
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func (c *BoundContract) Call(opts *CallOpts, result interface{}, method string, params ...interface{}) error {
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// Don't crash on a lazy user
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if opts == nil {
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opts = new(CallOpts)
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}
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// Pack the input, call and unpack the results
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input, err := c.abi.Pack(method, params...)
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if err != nil {
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return err
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}
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var (
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msg = ethereum.CallMsg{From: opts.From, To: &c.address, Data: input}
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ctx = ensureContext(opts.Context)
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code []byte
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output []byte
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)
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if opts.Pending {
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pb, ok := c.caller.(PendingContractCaller)
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if !ok {
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return ErrNoPendingState
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}
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output, err = pb.PendingCallContract(ctx, msg)
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if err == nil && len(output) == 0 {
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// Make sure we have a contract to operate on, and bail out otherwise.
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if code, err = pb.PendingCodeAt(ctx, c.address); err != nil {
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return err
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} else if len(code) == 0 {
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return ErrNoCode
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}
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}
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} else {
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output, err = c.caller.CallContract(ctx, msg, opts.BlockNumber)
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if err == nil && len(output) == 0 {
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// Make sure we have a contract to operate on, and bail out otherwise.
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if code, err = c.caller.CodeAt(ctx, c.address, opts.BlockNumber); err != nil {
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return err
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} else if len(code) == 0 {
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return ErrNoCode
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}
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}
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}
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if err != nil {
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return err
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}
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return c.abi.Unpack(result, method, output)
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}
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// Transact invokes the (paid) contract method with params as input values.
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func (c *BoundContract) Transact(opts *TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
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// Otherwise pack up the parameters and invoke the contract
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input, err := c.abi.Pack(method, params...)
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if err != nil {
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return nil, err
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}
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return c.transact(opts, &c.address, input)
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}
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// Transfer initiates a plain transaction to move funds to the contract, calling
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// its default method if one is available.
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func (c *BoundContract) Transfer(opts *TransactOpts) (*types.Transaction, error) {
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return c.transact(opts, &c.address, nil)
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}
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// transact executes an actual transaction invocation, first deriving any missing
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// authorization fields, and then scheduling the transaction for execution.
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func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, input []byte) (*types.Transaction, error) {
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var err error
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// Ensure a valid value field and resolve the account nonce
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value := opts.Value
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if value == nil {
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value = new(big.Int)
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}
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var nonce uint64
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if opts.Nonce == nil {
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nonce, err = c.transactor.PendingNonceAt(ensureContext(opts.Context), opts.From)
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if err != nil {
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return nil, fmt.Errorf("failed to retrieve account nonce: %v", err)
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}
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} else {
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nonce = opts.Nonce.Uint64()
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}
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// Figure out the gas allowance and gas price values
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gasPrice := opts.GasPrice
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if gasPrice == nil {
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gasPrice, err = c.transactor.SuggestGasPrice(ensureContext(opts.Context))
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if err != nil {
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return nil, fmt.Errorf("failed to suggest gas price: %v", err)
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}
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}
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gasLimit := opts.GasLimit
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if gasLimit == 0 {
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// Gas estimation cannot succeed without code for method invocations
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if contract != nil {
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if code, err := c.transactor.PendingCodeAt(ensureContext(opts.Context), c.address); err != nil {
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return nil, err
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} else if len(code) == 0 {
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return nil, ErrNoCode
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}
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}
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// If the contract surely has code (or code is not needed), estimate the transaction
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msg := ethereum.CallMsg{From: opts.From, To: contract, Value: value, Data: input}
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gasLimit, err = c.transactor.EstimateGas(ensureContext(opts.Context), msg)
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if err != nil {
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return nil, fmt.Errorf("failed to estimate gas needed: %v", err)
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}
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}
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// Create the transaction, sign it and schedule it for execution
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var rawTx *types.Transaction
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if contract == nil {
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rawTx = types.NewContractCreation(nonce, value, gasLimit, gasPrice, input)
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} else {
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rawTx = types.NewTransaction(nonce, c.address, value, gasLimit, gasPrice, input)
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}
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if opts.Signer == nil {
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return nil, errors.New("no signer to authorize the transaction with")
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}
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signedTx, err := opts.Signer(types.HomesteadSigner{}, opts.From, rawTx)
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if err != nil {
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return nil, err
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}
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if err := c.transactor.SendTransaction(ensureContext(opts.Context), signedTx); err != nil {
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return nil, err
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}
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return signedTx, nil
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}
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// FilterLogs filters contract logs for past blocks, returning the necessary
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// channels to construct a strongly typed bound iterator on top of them.
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func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
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// Don't crash on a lazy user
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if opts == nil {
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opts = new(FilterOpts)
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}
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// Append the event selector to the query parameters and construct the topic set
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query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)
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topics, err := makeTopics(query...)
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if err != nil {
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return nil, nil, err
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}
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// Start the background filtering
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logs := make(chan types.Log, 128)
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config := ethereum.FilterQuery{
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Addresses: []common.Address{c.address},
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Topics: topics,
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FromBlock: new(big.Int).SetUint64(opts.Start),
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}
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if opts.End != nil {
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config.ToBlock = new(big.Int).SetUint64(*opts.End)
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}
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/* TODO(karalabe): Replace the rest of the method below with this when supported
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sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
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*/
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buff, err := c.filterer.FilterLogs(ensureContext(opts.Context), config)
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if err != nil {
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return nil, nil, err
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}
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sub, err := event.NewSubscription(func(quit <-chan struct{}) error {
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for _, log := range buff {
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select {
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case logs <- log:
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case <-quit:
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return nil
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}
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}
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return nil
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}), nil
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if err != nil {
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return nil, nil, err
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}
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return logs, sub, nil
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}
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// WatchLogs filters subscribes to contract logs for future blocks, returning a
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// subscription object that can be used to tear down the watcher.
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func (c *BoundContract) WatchLogs(opts *WatchOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
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// Don't crash on a lazy user
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if opts == nil {
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opts = new(WatchOpts)
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}
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// Append the event selector to the query parameters and construct the topic set
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query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)
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topics, err := makeTopics(query...)
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if err != nil {
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return nil, nil, err
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}
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// Start the background filtering
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logs := make(chan types.Log, 128)
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config := ethereum.FilterQuery{
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Addresses: []common.Address{c.address},
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Topics: topics,
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}
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if opts.Start != nil {
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config.FromBlock = new(big.Int).SetUint64(*opts.Start)
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}
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sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
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if err != nil {
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return nil, nil, err
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}
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return logs, sub, nil
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}
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// UnpackLog unpacks a retrieved log into the provided output structure.
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func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log) error {
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if len(log.Data) > 0 {
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if err := c.abi.Unpack(out, event, log.Data); err != nil {
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return err
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}
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}
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var indexed abi.Arguments
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for _, arg := range c.abi.Events[event].Inputs {
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if arg.Indexed {
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indexed = append(indexed, arg)
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}
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}
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return parseTopics(out, indexed, log.Topics[1:])
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}
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// ensureContext is a helper method to ensure a context is not nil, even if the
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// user specified it as such.
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func ensureContext(ctx context.Context) context.Context {
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if ctx == nil {
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return context.TODO()
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}
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return ctx
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}
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