multi: Add ETHSwapV0.

Have the eth harness start with a contract. Add contract bindings and
basic calls to clients.

client/asset/eth/eth.go

@@ -19,6 +19,7 @@ import (
 	"decred.org/dcrdex/server/asset/eth"
 	"github.com/decred/dcrd/dcrutil/v3"
 	"github.com/ethereum/go-ethereum/accounts"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/node"
@@ -103,13 +104,17 @@ type ethFetcher interface {
 	blockNumber(ctx context.Context) (uint64, error)
 	connect(ctx context.Context, node *node.Node, contractAddr common.Address) error
 	importAccount(pw string, privKeyB []byte) (*accounts.Account, error)
+	initiate(opts *bind.TransactOpts, netID int64, refundTimestamp int64, secretHash [32]byte, participant common.Address) (*types.Transaction, error)
 	lock(ctx context.Context, acct *accounts.Account) error
 	locked(ctx context.Context, acct *accounts.Account) (bool, error)
 	nodeInfo(ctx context.Context) (*p2p.NodeInfo, error)
 	pendingTransactions(ctx context.Context) ([]*types.Transaction, error)
 	transactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
+	redeem(opts *bind.TransactOpts, netID int64, secret, secretHash [32]byte) (*types.Transaction, error)
+	refund(opts *bind.TransactOpts, netID int64, secretHash [32]byte) (*types.Transaction, error)
 	sendToAddr(ctx context.Context, acct *accounts.Account, addr common.Address, amt, gasFee *big.Int) (common.Hash, error)
 	shutdown()
+	swap(ctx context.Context, from *accounts.Account, secretHash [32]byte) (*eth.ETHSwapSwap, error)
 	syncStatus(ctx context.Context) (bool, float32, error)
 	unlock(ctx context.Context, pw string, acct *accounts.Account) error
 }

client/asset/eth/eth_test.go

@@ -11,7 +11,9 @@ import (
 	"testing"
 
 	"decred.org/dcrdex/dex"
+	"decred.org/dcrdex/server/asset/eth"
 	"github.com/ethereum/go-ethereum/accounts"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/node"
@@ -77,6 +79,18 @@ func (n *testNode) blockNumber(ctx context.Context) (uint64, error) {
 func (n *testNode) pendingTransactions(ctx context.Context) ([]*types.Transaction, error) {
 	return nil, nil
 }
+func (n *testNode) initiate(opts *bind.TransactOpts, netID int64, refundTimestamp int64, secretHash [32]byte, participant common.Address) (*types.Transaction, error) {
+	return nil, nil
+}
+func (n *testNode) redeem(opts *bind.TransactOpts, netID int64, secret, secretHash [32]byte) (*types.Transaction, error) {
+	return nil, nil
+}
+func (n *testNode) refund(opts *bind.TransactOpts, netID int64, secretHash [32]byte) (*types.Transaction, error) {
+	return nil, nil
+}
+func (n *testNode) swap(ctx context.Context, from *accounts.Account, secretHash [32]byte) (*eth.ETHSwapSwap, error) {
+	return nil, nil
+}
 func (n *testNode) transactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
 	return nil, nil
 }

client/asset/eth/rpcclient.go

@@ -10,7 +10,9 @@ import (
 	"fmt"
 	"math/big"
 
+	"decred.org/dcrdex/server/asset/eth"
 	"github.com/ethereum/go-ethereum/accounts"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -32,6 +34,7 @@ type rpcclient struct {
 	// ec wraps the client with some useful calls.
 	ec *ethclient.Client
 	n  *node.Node
+	es *eth.ETHSwap
 }
 
 // connect connects to a node. It then wraps ethclient's client and
@@ -44,6 +47,10 @@ func (c *rpcclient) connect(ctx context.Context, node *node.Node, contractAddr c
 	c.c = client
 	c.ec = ethclient.NewClient(client)
 	c.n = node
+	c.es, err = eth.NewETHSwap(contractAddr, c.ec)
+	if err != nil {
+		return fmt.Errorf("unable to find swap contract: %v", err)
+	}
 	return nil
 }
 
@@ -242,3 +249,59 @@ func (c *rpcclient) wallet(acct accounts.Account) (accounts.Wallet, error) {
 	}
 	return wallet, nil
 }
+
+// swap gets a swap keyed by secretHash in the contract.
+func (c *rpcclient) swap(ctx context.Context, from *accounts.Account, secretHash [32]byte) (*eth.ETHSwapSwap, error) {
+	callOpts := &bind.CallOpts{
+		Pending: true,
+		From:    from.Address,
+		Context: ctx,
+	}
+	swap, err := c.es.Swap(callOpts, secretHash)
+	if err != nil {
+		return nil, err
+	}
+	return &swap, nil
+}
+
+// initiate creates a swap contract. The initiator will be the account at
+// txOpts.From. Any on-chain failure, such as this secret hash already existing
+// in the swaps map, will not cause this to error.
+func (c *rpcclient) initiate(txOpts *bind.TransactOpts, netID int64, refundTimestamp int64, secretHash [32]byte, participant common.Address) (*types.Transaction, error) {
+	wallet, err := c.wallet(accounts.Account{Address: txOpts.From})
+	if err != nil {
+		return nil, err
+	}
+	txOpts.Signer = func(addr common.Address, tx *types.Transaction) (*types.Transaction, error) {
+		return wallet.SignTx(accounts.Account{Address: addr}, tx, big.NewInt(netID))
+	}
+	return c.es.Initiate(txOpts, big.NewInt(refundTimestamp), secretHash, participant)
+}
+
+// redeem redeems a swap contract. The redeemer will be the account at txOpts.From.
+// Any on-chain failure, such as this secret not mathing the hash, will not cause
+// this to error.
+func (c *rpcclient) redeem(txOpts *bind.TransactOpts, netID int64, secret, secretHash [32]byte) (*types.Transaction, error) {
+	wallet, err := c.wallet(accounts.Account{Address: txOpts.From})
+	if err != nil {
+		return nil, err
+	}
+	txOpts.Signer = func(addr common.Address, tx *types.Transaction) (*types.Transaction, error) {
+		return wallet.SignTx(accounts.Account{Address: addr}, tx, big.NewInt(netID))
+	}
+	return c.es.Redeem(txOpts, secret, secretHash)
+}
+
+// refund refunds a swap contract. The refunder will be the account at txOpts.From.
+// Any on-chain failure, such as the locktime not being past, will not cause
+// this to error.
+func (c *rpcclient) refund(txOpts *bind.TransactOpts, netID int64, secretHash [32]byte) (*types.Transaction, error) {
+	wallet, err := c.wallet(accounts.Account{Address: txOpts.From})
+	if err != nil {
+		return nil, err
+	}
+	txOpts.Signer = func(addr common.Address, tx *types.Transaction) (*types.Transaction, error) {
+		return wallet.SignTx(accounts.Account{Address: addr}, tx, big.NewInt(netID))
+	}
+	return c.es.Refund(txOpts, secretHash)
+}