// Copyright 2015 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 ( "context" "errors" "fmt" "math/big" "github.com/ava-labs/coreth/accounts/abi" "github.com/ava-labs/coreth/core/types" "github.com/ava-labs/go-ethereum" "github.com/ava-labs/go-ethereum/common" "github.com/ava-labs/go-ethereum/crypto" "github.com/ava-labs/go-ethereum/event" ) // SignerFn is a signer function callback when a contract requires a method to // sign the transaction before submission. type SignerFn func(types.Signer, common.Address, *types.Transaction) (*types.Transaction, error) // CallOpts is the collection of options to fine tune a contract call request. type CallOpts struct { Pending bool // Whether to operate on the pending state or the last known one From common.Address // Optional the sender address, otherwise the first account is used BlockNumber *big.Int // Optional the block number on which the call should be performed Context context.Context // Network context to support cancellation and timeouts (nil = no timeout) } // TransactOpts is the collection of authorization data required to create a // valid Ethereum transaction. type TransactOpts struct { From 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 uint64 // Gas limit to set for the transaction execution (0 = estimate) Context context.Context // Network context to support cancellation and timeouts (nil = no timeout) } // FilterOpts is the collection of options to fine tune filtering for events // within a bound contract. type FilterOpts struct { Start uint64 // Start of the queried range End *uint64 // End of the range (nil = latest) Context context.Context // Network context to support cancellation and timeouts (nil = no timeout) } // WatchOpts is the collection of options to fine tune subscribing for events // within a bound contract. type WatchOpts struct { Start *uint64 // Start of the queried range (nil = latest) Context context.Context // Network context to support cancellation and timeouts (nil = no timeout) } // 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 filterer ContractFilterer // Event filtering 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, filterer ContractFilterer) *BoundContract { return &BoundContract{ address: address, abi: abi, caller: caller, transactor: transactor, filterer: filterer, } } // DeployContract deploys a contract onto the Ethereum blockchain and binds the // deployment address with a Go wrapper. func DeployContract(opts *TransactOpts, abi abi.ABI, bytecode []byte, backend ContractBackend, params ...interface{}) (common.Address, *types.Transaction, *BoundContract, error) { // Otherwise try to deploy the contract c := NewBoundContract(common.Address{}, abi, backend, backend, backend) input, err := c.abi.Pack("", params...) if err != nil { return common.Address{}, nil, nil, err } tx, err := c.transact(opts, nil, append(bytecode, input...)) if err != nil { return common.Address{}, nil, nil, err } c.address = crypto.CreateAddress(opts.From, tx.Nonce()) return c.address, tx, c, nil } // 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(opts *CallOpts, result interface{}, method string, params ...interface{}) error { // Don't crash on a lazy user if opts == nil { opts = new(CallOpts) } // Pack the input, call and unpack the results input, err := c.abi.Pack(method, params...) if err != nil { return err } var ( msg = ethereum.CallMsg{From: opts.From, To: &c.address, Data: input} ctx = ensureContext(opts.Context) code []byte output []byte ) if opts.Pending { pb, ok := c.caller.(PendingContractCaller) if !ok { return ErrNoPendingState } output, err = pb.PendingCallContract(ctx, msg) if err == nil && len(output) == 0 { // Make sure we have a contract to operate on, and bail out otherwise. if code, err = pb.PendingCodeAt(ctx, c.address); err != nil { return err } else if len(code) == 0 { return ErrNoCode } } } else { output, err = c.caller.CallContract(ctx, msg, opts.BlockNumber) if err == nil && len(output) == 0 { // Make sure we have a contract to operate on, and bail out otherwise. if code, err = c.caller.CodeAt(ctx, c.address, opts.BlockNumber); err != nil { return err } else if len(code) == 0 { return ErrNoCode } } } if err != nil { return err } return c.abi.Unpack(result, method, output) } // Transact invokes the (paid) contract method with params as input values. func (c *BoundContract) Transact(opts *TransactOpts, method string, params ...interface{}) (*types.Transaction, error) { // Otherwise pack up the parameters and invoke the contract input, err := c.abi.Pack(method, params...) if err != nil { return nil, err } return c.transact(opts, &c.address, input) } // Transfer initiates a plain transaction to move funds to the contract, calling // its default method if one is available. func (c *BoundContract) Transfer(opts *TransactOpts) (*types.Transaction, error) { return c.transact(opts, &c.address, nil) } // transact executes an actual transaction invocation, first deriving any missing // authorization fields, and then scheduling the transaction for execution. func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, input []byte) (*types.Transaction, error) { var err error // Ensure a valid value field and resolve the account nonce value := opts.Value if value == nil { value = new(big.Int) } var nonce uint64 if opts.Nonce == nil { nonce, err = c.transactor.PendingNonceAt(ensureContext(opts.Context), opts.From) 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.SuggestGasPrice(ensureContext(opts.Context)) if err != nil { return nil, fmt.Errorf("failed to suggest gas price: %v", err) } } gasLimit := opts.GasLimit if gasLimit == 0 { // Gas estimation cannot succeed without code for method invocations if contract != nil { if code, err := c.transactor.PendingCodeAt(ensureContext(opts.Context), c.address); err != nil { return nil, err } else if len(code) == 0 { return nil, ErrNoCode } } // If the contract surely has code (or code is not needed), estimate the transaction msg := ethereum.CallMsg{From: opts.From, To: contract, Value: value, Data: input} gasLimit, err = c.transactor.EstimateGas(ensureContext(opts.Context), msg) if err != nil { return nil, fmt.Errorf("failed to estimate gas needed: %v", err) } } // Create the transaction, sign it and schedule it for execution var rawTx *types.Transaction if contract == nil { rawTx = types.NewContractCreation(nonce, value, gasLimit, gasPrice, input) } else { 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(types.HomesteadSigner{}, opts.From, rawTx) if err != nil { return nil, err } if err := c.transactor.SendTransaction(ensureContext(opts.Context), signedTx); err != nil { return nil, err } return signedTx, nil } // FilterLogs filters contract logs for past blocks, returning the necessary // channels to construct a strongly typed bound iterator on top of them. func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) { // Don't crash on a lazy user if opts == nil { opts = new(FilterOpts) } // Append the event selector to the query parameters and construct the topic set query = append([][]interface{}{{c.abi.Events[name].ID()}}, query...) topics, err := makeTopics(query...) if err != nil { return nil, nil, err } // Start the background filtering logs := make(chan types.Log, 128) config := ethereum.FilterQuery{ Addresses: []common.Address{c.address}, Topics: topics, FromBlock: new(big.Int).SetUint64(opts.Start), } if opts.End != nil { config.ToBlock = new(big.Int).SetUint64(*opts.End) } /* TODO(karalabe): Replace the rest of the method below with this when supported sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs) */ buff, err := c.filterer.FilterLogs(ensureContext(opts.Context), config) if err != nil { return nil, nil, err } sub, err := event.NewSubscription(func(quit <-chan struct{}) error { for _, log := range buff { select { case logs <- log: case <-quit: return nil } } return nil }), nil if err != nil { return nil, nil, err } return logs, sub, nil } // WatchLogs filters subscribes to contract logs for future blocks, returning a // subscription object that can be used to tear down the watcher. func (c *BoundContract) WatchLogs(opts *WatchOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) { // Don't crash on a lazy user if opts == nil { opts = new(WatchOpts) } // Append the event selector to the query parameters and construct the topic set query = append([][]interface{}{{c.abi.Events[name].ID()}}, query...) topics, err := makeTopics(query...) if err != nil { return nil, nil, err } // Start the background filtering logs := make(chan types.Log, 128) config := ethereum.FilterQuery{ Addresses: []common.Address{c.address}, Topics: topics, } if opts.Start != nil { config.FromBlock = new(big.Int).SetUint64(*opts.Start) } sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs) if err != nil { return nil, nil, err } return logs, sub, nil } // UnpackLog unpacks a retrieved log into the provided output structure. func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log) error { if len(log.Data) > 0 { if err := c.abi.Unpack(out, event, log.Data); err != nil { return err } } var indexed abi.Arguments for _, arg := range c.abi.Events[event].Inputs { if arg.Indexed { indexed = append(indexed, arg) } } return parseTopics(out, indexed, log.Topics[1:]) } // UnpackLogIntoMap unpacks a retrieved log into the provided map. func (c *BoundContract) UnpackLogIntoMap(out map[string]interface{}, event string, log types.Log) error { if len(log.Data) > 0 { if err := c.abi.UnpackIntoMap(out, event, log.Data); err != nil { return err } } var indexed abi.Arguments for _, arg := range c.abi.Events[event].Inputs { if arg.Indexed { indexed = append(indexed, arg) } } return parseTopicsIntoMap(out, indexed, log.Topics[1:]) } // ensureContext is a helper method to ensure a context is not nil, even if the // user specified it as such. func ensureContext(ctx context.Context) context.Context { if ctx == nil { return context.TODO() } return ctx }