[WIP]Enable payments in Celo Dollars (ethereum#109)

* Add support C$ transaction

Add support for non-native currency. Those transactions are processed if
contract addresses are available and passed via command-line.

* Address Asa's comments

* Make more code non-native currency aware

* Remove GasCurrencyAddress completely; state transition will accept any valid currency address contract

* Fix refund logic

* Pre-check gas balance in custom currency

* Limit gas usage for debitFrom and creditTo

1. This prevents gas usage attack by malicious debitFrom and creditTo
methods
2. This prevents the chicken-and-egg problem of charging user for
refunding before actually refunding.

* Address Asa's comments

* Fix an integer underflow in gas refund

* all tests are fixed other than the tracer tests

* got most of the tracer tests to work

* Fix lint issues

accounts/abi/bind/backends/simulated.go

@@ -410,14 +410,15 @@ type callmsg struct {
 	ethereum.CallMsg
 }
 
-func (m callmsg) From() common.Address { return m.CallMsg.From }
-func (m callmsg) Nonce() uint64        { return 0 }
-func (m callmsg) CheckNonce() bool     { return false }
-func (m callmsg) To() *common.Address  { return m.CallMsg.To }
-func (m callmsg) GasPrice() *big.Int   { return m.CallMsg.GasPrice }
-func (m callmsg) Gas() uint64          { return m.CallMsg.Gas }
-func (m callmsg) Value() *big.Int      { return m.CallMsg.Value }
-func (m callmsg) Data() []byte         { return m.CallMsg.Data }
+func (m callmsg) From() common.Address         { return m.CallMsg.From }
+func (m callmsg) Nonce() uint64                { return 0 }
+func (m callmsg) CheckNonce() bool             { return false }
+func (m callmsg) To() *common.Address          { return m.CallMsg.To }
+func (m callmsg) GasPrice() *big.Int           { return m.CallMsg.GasPrice }
+func (m callmsg) GasCurrency() *common.Address { return m.CallMsg.GasCurrency }
+func (m callmsg) Gas() uint64                  { return m.CallMsg.Gas }
+func (m callmsg) Value() *big.Int              { return m.CallMsg.Value }
+func (m callmsg) Data() []byte                 { return m.CallMsg.Data }
 
 // filterBackend implements filters.Backend to support filtering for logs without
 // taking bloom-bits acceleration structures into account.

accounts/abi/bind/base.go

@@ -49,9 +49,10 @@ type TransactOpts struct {
 	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)
+	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)
+	GasCurrency *common.Address // Gas currency to be used for transaction (nil = default currency = Celo Gold)
+	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)
 }
@@ -207,6 +208,14 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 			return nil, fmt.Errorf("failed to suggest gas price: %v", err)
 		}
 	}
+	gasCurrency := opts.GasCurrency
+	// TODO(ashishb): Add SuggestGasCurrency to Transactor to get gas currency
+	// Otherwise, the user might not be able to pay in non-native currency for contract
+	// deployment. Paying for Contract deployment in non-native currency might not work right now.
+	// Only paying for token transfer in non-native currency is supported.
+	//if gasCurrency == 0 {
+	//	gasCurrency = c.transactor.SuggestGasCurrency(opts.Context)
+	//}
 	gasLimit := opts.GasLimit
 	if gasLimit == 0 {
 		// Gas estimation cannot succeed without code for method invocations
@@ -227,9 +236,9 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 	// 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)
+		rawTx = types.NewContractCreation(nonce, value, gasLimit, gasPrice, gasCurrency, input)
 	} else {
-		rawTx = types.NewTransaction(nonce, c.address, value, gasLimit, gasPrice, input)
+		rawTx = types.NewTransaction(nonce, c.address, value, gasLimit, gasPrice, gasCurrency, input)
 	}
 	if opts.Signer == nil {
 		return nil, errors.New("no signer to authorize the transaction with")

accounts/abi/bind/util_test.go

@@ -60,7 +60,7 @@ func TestWaitDeployed(t *testing.T) {
 		)
 
 		// Create the transaction.
-		tx := types.NewContractCreation(0, big.NewInt(0), test.gas, big.NewInt(1), common.FromHex(test.code))
+		tx := types.NewContractCreation(0, big.NewInt(0), test.gas, big.NewInt(1), nil, common.FromHex(test.code))
 		tx, _ = types.SignTx(tx, types.HomesteadSigner{}, testKey)
 
 		// Wait for it to get mined in the background.

cmd/faucet/faucet.go

@@ -472,7 +472,7 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 			amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil))
 			amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil))
 
-			tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil)
+			tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil, nil)
 			signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainID)
 			if err != nil {
 				f.lock.Unlock()

core/bench_test.go

@@ -86,7 +86,7 @@ func genValueTx(nbytes int) func(int, *BlockGen) {
 		toaddr := common.Address{}
 		data := make([]byte, nbytes)
 		gas, _ := IntrinsicGas(data, false, false)
-		tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, data), types.HomesteadSigner{}, benchRootKey)
+		tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, nil, data), types.HomesteadSigner{}, benchRootKey)
 		gen.AddTx(tx)
 	}
 }
@@ -126,6 +126,7 @@ func genTxRing(naccounts int) func(int, *BlockGen) {
 				params.TxGas,
 				nil,
 				nil,
+				nil,
 			)
 			tx, _ = types.SignTx(tx, types.HomesteadSigner{}, ringKeys[from])
 			gen.AddTx(tx)

core/blockchain_test.go

@@ -620,7 +620,7 @@ func TestFastVsFullChains(t *testing.T) {
 		// If the block number is multiple of 3, send a few bonus transactions to the miner
 		if i%3 == 2 {
 			for j := 0; j < i%4+1; j++ {
-				tx, err := types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{0x00}, big.NewInt(1000), params.TxGas, nil, nil), signer, key)
+				tx, err := types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{0x00}, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key)
 				if err != nil {
 					panic(err)
 				}
@@ -793,8 +793,8 @@ func TestChainTxReorgs(t *testing.T) {
 	// Create two transactions shared between the chains:
 	//  - postponed: transaction included at a later block in the forked chain
 	//  - swapped: transaction included at the same block number in the forked chain
-	postponed, _ := types.SignTx(types.NewTransaction(0, addr1, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
-	swapped, _ := types.SignTx(types.NewTransaction(1, addr1, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
+	postponed, _ := types.SignTx(types.NewTransaction(0, addr1, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key1)
+	swapped, _ := types.SignTx(types.NewTransaction(1, addr1, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key1)
 
 	// Create two transactions that will be dropped by the forked chain:
 	//  - pastDrop: transaction dropped retroactively from a past block
@@ -810,13 +810,13 @@ func TestChainTxReorgs(t *testing.T) {
 	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
-			pastDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
+			pastDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key2)
 
 			gen.AddTx(pastDrop)  // This transaction will be dropped in the fork from below the split point
 			gen.AddTx(postponed) // This transaction will be postponed till block #3 in the fork
 
 		case 2:
-			freshDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
+			freshDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key2)
 
 			gen.AddTx(freshDrop) // This transaction will be dropped in the fork from exactly at the split point
 			gen.AddTx(swapped)   // This transaction will be swapped out at the exact height
@@ -835,18 +835,18 @@ func TestChainTxReorgs(t *testing.T) {
 	chain, _ = GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
-			pastAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
+			pastAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key3)
 			gen.AddTx(pastAdd) // This transaction needs to be injected during reorg
 
 		case 2:
 			gen.AddTx(postponed) // This transaction was postponed from block #1 in the original chain
 			gen.AddTx(swapped)   // This transaction was swapped from the exact current spot in the original chain
 
-			freshAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
+			freshAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key3)
 			gen.AddTx(freshAdd) // This transaction will be added exactly at reorg time
 
 		case 3:
-			futureAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
+			futureAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key3)
 			gen.AddTx(futureAdd) // This transaction will be added after a full reorg
 		}
 	})
@@ -903,7 +903,7 @@ func TestLogReorgs(t *testing.T) {
 	blockchain.SubscribeRemovedLogsEvent(rmLogsCh)
 	chain, _ := GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 2, func(i int, gen *BlockGen) {
 		if i == 1 {
-			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), code), signer, key1)
+			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), nil, code), signer, key1)
 			if err != nil {
 				t.Fatalf("failed to create tx: %v", err)
 			}
@@ -952,7 +952,7 @@ func TestReorgSideEvent(t *testing.T) {
 	}
 
 	replacementBlocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 4, func(i int, gen *BlockGen) {
-		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), nil), signer, key1)
+		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), nil, nil), signer, key1)
 		if i == 2 {
 			gen.OffsetTime(-9)
 		}
@@ -1080,7 +1080,7 @@ func TestEIP155Transition(t *testing.T) {
 			tx      *types.Transaction
 			err     error
 			basicTx = func(signer types.Signer) (*types.Transaction, error) {
-				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil), signer, key)
+				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil, nil), signer, key)
 			}
 		)
 		switch i {
@@ -1143,7 +1143,7 @@ func TestEIP155Transition(t *testing.T) {
 			tx      *types.Transaction
 			err     error
 			basicTx = func(signer types.Signer) (*types.Transaction, error) {
-				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil), signer, key)
+				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil, nil), signer, key)
 			}
 		)
 		if i == 0 {
@@ -1190,11 +1190,11 @@ func TestEIP161AccountRemoval(t *testing.T) {
 		)
 		switch i {
 		case 0:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil, nil), signer, key)
 		case 1:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil, nil), signer, key)
 		case 2:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil, nil), signer, key)
 		}
 		if err != nil {
 			t.Fatal(err)
@@ -1403,7 +1403,7 @@ func benchmarkLargeNumberOfValueToNonexisting(b *testing.B, numTxs, numBlocks in
 			uniq := uint64(i*numTxs + txi)
 			recipient := recipientFn(uniq)
 			//recipient := common.BigToAddress(big.NewInt(0).SetUint64(1337 + uniq))
-			tx, err := types.SignTx(types.NewTransaction(uniq, recipient, big.NewInt(1), params.TxGas, big.NewInt(1), nil), signer, testBankKey)
+			tx, err := types.SignTx(types.NewTransaction(uniq, recipient, big.NewInt(1), params.TxGas, big.NewInt(1), nil, nil), signer, testBankKey)
 			if err != nil {
 				b.Error(err)
 			}

core/chain_makers_test.go

@@ -54,13 +54,13 @@ func ExampleGenerateChain() {
 		switch i {
 		case 0:
 			// In block 1, addr1 sends addr2 some ether.
-			tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil), signer, key1)
+			tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil, nil), signer, key1)
 			gen.AddTx(tx)
 		case 1:
 			// In block 2, addr1 sends some more ether to addr2.
 			// addr2 passes it on to addr3.
-			tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
-			tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
+			tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key1)
+			tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil, nil), signer, key2)
 			gen.AddTx(tx1)
 			gen.AddTx(tx2)
 		case 2:

core/rawdb/accessors_indexes_test.go

@@ -29,9 +29,9 @@ import (
 func TestLookupStorage(t *testing.T) {
 	db := ethdb.NewMemDatabase()
 
-	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), 1111, big.NewInt(11111), []byte{0x11, 0x11, 0x11})
-	tx2 := types.NewTransaction(2, common.BytesToAddress([]byte{0x22}), big.NewInt(222), 2222, big.NewInt(22222), []byte{0x22, 0x22, 0x22})
-	tx3 := types.NewTransaction(3, common.BytesToAddress([]byte{0x33}), big.NewInt(333), 3333, big.NewInt(33333), []byte{0x33, 0x33, 0x33})
+	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), 1111, big.NewInt(11111), nil, []byte{0x11, 0x11, 0x11})
+	tx2 := types.NewTransaction(2, common.BytesToAddress([]byte{0x22}), big.NewInt(222), 2222, big.NewInt(22222), nil, []byte{0x22, 0x22, 0x22})
+	tx3 := types.NewTransaction(3, common.BytesToAddress([]byte{0x33}), big.NewInt(333), 3333, big.NewInt(33333), nil, []byte{0x33, 0x33, 0x33})
 	txs := []*types.Transaction{tx1, tx2, tx3}
 
 	block := types.NewBlock(&types.Header{Number: big.NewInt(314)}, txs, nil, nil)