Merge pull request #2159 from zsfelfoldi/light-backend

eth: separate common and full node-specific API and backend service

5 files changed, 77 insertions, 48 deletions

diff --git a/accounts/abi/bind/backend.go b/accounts/abi/bind/backend.go
index 65806aef4..bec742c29 100644
--- a/accounts/abi/bind/backend.go
+++ b/accounts/abi/bind/backend.go
@@ -22,6 +22,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"golang.org/x/net/context"
 )
 
 // ErrNoCode is returned by call and transact operations for which the requested
@@ -35,12 +36,12 @@ type ContractCaller interface {
 	// HasCode checks if the contract at the given address has any code associated
 	// with it or not. This is needed to differentiate between contract internal
 	// errors and the local chain being out of sync.
-	HasCode(contract common.Address, pending bool) (bool, error)
+	HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error)
 
 	// ContractCall executes an Ethereum contract call with the specified data as
 	// the input. The pending flag requests execution against the pending block, not
 	// the stable head of the chain.
-	ContractCall(contract common.Address, data []byte, pending bool) ([]byte, error)
+	ContractCall(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error)
 }
 
 // ContractTransactor defines the methods needed to allow operating with contract
@@ -50,26 +51,26 @@ type ContractCaller interface {
 type ContractTransactor interface {
 	// PendingAccountNonce retrieves the current pending nonce associated with an
 	// account.
-	PendingAccountNonce(account common.Address) (uint64, error)
+	PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error)
 
 	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
 	// execution of a transaction.
-	SuggestGasPrice() (*big.Int, error)
+	SuggestGasPrice(ctx context.Context) (*big.Int, error)
 
 	// HasCode checks if the contract at the given address has any code associated
 	// with it or not. This is needed to differentiate between contract internal
 	// errors and the local chain being out of sync.
-	HasCode(contract common.Address, pending bool) (bool, error)
+	HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error)
 
 	// EstimateGasLimit tries to estimate the gas needed to execute a specific
 	// transaction based on the current pending state of the backend blockchain.
 	// There is no guarantee that this is the true gas limit requirement as other
 	// transactions may be added or removed by miners, but it should provide a basis
 	// for setting a reasonable default.
-	EstimateGasLimit(sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error)
+	EstimateGasLimit(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error)
 
 	// SendTransaction injects the transaction into the pending pool for execution.
-	SendTransaction(tx *types.Transaction) error
+	SendTransaction(ctx context.Context, tx *types.Transaction) error
 }
 
 // ContractBackend defines the methods needed to allow operating with contract
@@ -84,28 +85,28 @@ type ContractBackend interface {
 	// HasCode checks if the contract at the given address has any code associated
 	// with it or not. This is needed to differentiate between contract internal
 	// errors and the local chain being out of sync.
-	HasCode(contract common.Address, pending bool) (bool, error)
+	HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error)
 
 	// ContractCall executes an Ethereum contract call with the specified data as
 	// the input. The pending flag requests execution against the pending block, not
 	// the stable head of the chain.
-	ContractCall(contract common.Address, data []byte, pending bool) ([]byte, error)
+	ContractCall(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error)
 
 	// PendingAccountNonce retrieves the current pending nonce associated with an
 	// account.
-	PendingAccountNonce(account common.Address) (uint64, error)
+	PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error)
 
 	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
 	// execution of a transaction.
-	SuggestGasPrice() (*big.Int, error)
+	SuggestGasPrice(ctx context.Context) (*big.Int, error)
 
 	// EstimateGasLimit tries to estimate the gas needed to execute a specific
 	// transaction based on the current pending state of the backend blockchain.
 	// There is no guarantee that this is the true gas limit requirement as other
 	// transactions may be added or removed by miners, but it should provide a basis
 	// for setting a reasonable default.
-	EstimateGasLimit(sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error)
+	EstimateGasLimit(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error)
 
 	// SendTransaction injects the transaction into the pending pool for execution.
-	SendTransaction(tx *types.Transaction) error
+	SendTransaction(ctx context.Context, tx *types.Transaction) error
 }
diff --git a/accounts/abi/bind/backends/nil.go b/accounts/abi/bind/backends/nil.go
index f10bb61ac..54b222f1f 100644
--- a/accounts/abi/bind/backends/nil.go
+++ b/accounts/abi/bind/backends/nil.go
@@ -22,6 +22,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"golang.org/x/net/context"
 )
 
 // This nil assignment ensures compile time that nilBackend implements bind.ContractBackend.
@@ -32,16 +33,22 @@ var _ bind.ContractBackend = (*nilBackend)(nil)
 // wrappers without calling any methods on them.
 type nilBackend struct{}
 
-func (*nilBackend) ContractCall(common.Address, []byte, bool) ([]byte, error) {
+func (*nilBackend) ContractCall(context.Context, common.Address, []byte, bool) ([]byte, error) {
 	panic("not implemented")
 }
-func (*nilBackend) EstimateGasLimit(common.Address, *common.Address, *big.Int, []byte) (*big.Int, error) {
+func (*nilBackend) EstimateGasLimit(context.Context, common.Address, *common.Address, *big.Int, []byte) (*big.Int, error) {
+	panic("not implemented")
+}
+func (*nilBackend) HasCode(context.Context, common.Address, bool) (bool, error) {
+	panic("not implemented")
+}
+func (*nilBackend) SuggestGasPrice(context.Context) (*big.Int, error) { panic("not implemented") }
+func (*nilBackend) PendingAccountNonce(context.Context, common.Address) (uint64, error) {
+	panic("not implemented")
+}
+func (*nilBackend) SendTransaction(context.Context, *types.Transaction) error {
 	panic("not implemented")
 }
-func (*nilBackend) HasCode(common.Address, bool) (bool, error)         { panic("not implemented") }
-func (*nilBackend) SuggestGasPrice() (*big.Int, error)                 { panic("not implemented") }
-func (*nilBackend) PendingAccountNonce(common.Address) (uint64, error) { panic("not implemented") }
-func (*nilBackend) SendTransaction(*types.Transaction) error           { panic("not implemented") }
 
 // NewNilBackend creates a new binding backend that can be used for instantiation
 // but will panic on any invocation. Its sole purpose is to help testing.
diff --git a/accounts/abi/bind/backends/remote.go b/accounts/abi/bind/backends/remote.go
index d903cbc8f..4793143e4 100644
--- a/accounts/abi/bind/backends/remote.go
+++ b/accounts/abi/bind/backends/remote.go
@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc"
+	"golang.org/x/net/context"
 )
 
 // This nil assignment ensures compile time that rpcBackend implements bind.ContractBackend.
@@ -80,18 +81,23 @@ type failure struct {
 //
 // This is currently painfully non-concurrent, but it will have to do until we
 // find the time for niceties like this :P
-func (b *rpcBackend) request(method string, params []interface{}) (json.RawMessage, error) {
+func (b *rpcBackend) request(ctx context.Context, method string, params []interface{}) (json.RawMessage, error) {
 	b.lock.Lock()
 	defer b.lock.Unlock()
 
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
 	// Ugly hack to serialize an empty list properly
 	if params == nil {
 		params = []interface{}{}
 	}
 	// Assemble the request object
+	reqID := int(atomic.AddUint32(&b.autoid, 1))
 	req := &request{
 		JSONRPC: "2.0",
-		ID:      int(atomic.AddUint32(&b.autoid, 1)),
+		ID:      reqID,
 		Method:  method,
 		Params:  params,
 	}
@@ -99,8 +105,17 @@ func (b *rpcBackend) request(method string, params []interface{}) (json.RawMessa
 		return nil, err
 	}
 	res := new(response)
-	if err := b.client.Recv(res); err != nil {
-		return nil, err
+	errc := make(chan error, 1)
+	go func() {
+		errc <- b.client.Recv(res)
+	}()
+	select {
+	case err := <-errc:
+		if err != nil {
+			return nil, err
+		}
+	case <-ctx.Done():
+		return nil, ctx.Err()
 	}
 	if res.Error != nil {
 		if res.Error.Message == bind.ErrNoCode.Error() {
@@ -113,13 +128,13 @@ func (b *rpcBackend) request(method string, params []interface{}) (json.RawMessa
 
 // HasCode implements ContractVerifier.HasCode by retrieving any code associated
 // with the contract from the remote node, and checking its size.
-func (b *rpcBackend) HasCode(contract common.Address, pending bool) (bool, error) {
+func (b *rpcBackend) HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error) {
 	// Execute the RPC code retrieval
 	block := "latest"
 	if pending {
 		block = "pending"
 	}
-	res, err := b.request("eth_getCode", []interface{}{contract.Hex(), block})
+	res, err := b.request(ctx, "eth_getCode", []interface{}{contract.Hex(), block})
 	if err != nil {
 		return false, err
 	}
@@ -133,7 +148,7 @@ func (b *rpcBackend) HasCode(contract common.Address, pending bool) (bool, error
 
 // ContractCall implements ContractCaller.ContractCall, delegating the execution of
 // a contract call to the remote node, returning the reply to for local processing.
-func (b *rpcBackend) ContractCall(contract common.Address, data []byte, pending bool) ([]byte, error) {
+func (b *rpcBackend) ContractCall(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error) {
 	// Pack up the request into an RPC argument
 	args := struct {
 		To   common.Address `json:"to"`
@@ -147,7 +162,7 @@ func (b *rpcBackend) ContractCall(contract common.Address, data []byte, pending
 	if pending {
 		block = "pending"
 	}
-	res, err := b.request("eth_call", []interface{}{args, block})
+	res, err := b.request(ctx, "eth_call", []interface{}{args, block})
 	if err != nil {
 		return nil, err
 	}
@@ -161,8 +176,8 @@ func (b *rpcBackend) ContractCall(contract common.Address, data []byte, pending
 
 // PendingAccountNonce implements ContractTransactor.PendingAccountNonce, delegating
 // the current account nonce retrieval to the remote node.
-func (b *rpcBackend) PendingAccountNonce(account common.Address) (uint64, error) {
-	res, err := b.request("eth_getTransactionCount", []interface{}{account.Hex(), "pending"})
+func (b *rpcBackend) PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error) {
+	res, err := b.request(ctx, "eth_getTransactionCount", []interface{}{account.Hex(), "pending"})
 	if err != nil {
 		return 0, err
 	}
@@ -179,8 +194,8 @@ func (b *rpcBackend) PendingAccountNonce(account common.Address) (uint64, error)
 
 // SuggestGasPrice implements ContractTransactor.SuggestGasPrice, delegating the
 // gas price oracle request to the remote node.
-func (b *rpcBackend) SuggestGasPrice() (*big.Int, error) {
-	res, err := b.request("eth_gasPrice", nil)
+func (b *rpcBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
+	res, err := b.request(ctx, "eth_gasPrice", nil)
 	if err != nil {
 		return nil, err
 	}
@@ -197,7 +212,7 @@ func (b *rpcBackend) SuggestGasPrice() (*big.Int, error) {
 
 // EstimateGasLimit implements ContractTransactor.EstimateGasLimit, delegating
 // the gas estimation to the remote node.
-func (b *rpcBackend) EstimateGasLimit(sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
+func (b *rpcBackend) EstimateGasLimit(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
 	// Pack up the request into an RPC argument
 	args := struct {
 		From  common.Address  `json:"from"`
@@ -211,7 +226,7 @@ func (b *rpcBackend) EstimateGasLimit(sender common.Address, contract *common.Ad
 		Value: rpc.NewHexNumber(value),
 	}
 	// Execute the RPC call and retrieve the response
-	res, err := b.request("eth_estimateGas", []interface{}{args})
+	res, err := b.request(ctx, "eth_estimateGas", []interface{}{args})
 	if err != nil {
 		return nil, err
 	}
@@ -228,12 +243,12 @@ func (b *rpcBackend) EstimateGasLimit(sender common.Address, contract *common.Ad
 
 // SendTransaction implements ContractTransactor.SendTransaction, delegating the
 // raw transaction injection to the remote node.
-func (b *rpcBackend) SendTransaction(tx *types.Transaction) error {
+func (b *rpcBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
 	data, err := rlp.EncodeToBytes(tx)
 	if err != nil {
 		return err
 	}
-	res, err := b.request("eth_sendRawTransaction", []interface{}{common.ToHex(data)})
+	res, err := b.request(ctx, "eth_sendRawTransaction", []interface{}{common.ToHex(data)})
 	if err != nil {
 		return err
 	}
diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 54b1ce603..490da82a6 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
+	"golang.org/x/net/context"
 )
 
 // Default chain configuration which sets homestead phase at block 0 (i.e. no frontier)
@@ -80,7 +81,7 @@ func (b *SimulatedBackend) Rollback() {
 
 // HasCode implements ContractVerifier.HasCode, checking whether there is any
 // code associated with a certain account in the blockchain.
-func (b *SimulatedBackend) HasCode(contract common.Address, pending bool) (bool, error) {
+func (b *SimulatedBackend) HasCode(ctx context.Context, contract common.Address, pending bool) (bool, error) {
 	if pending {
 		return len(b.pendingState.GetCode(contract)) > 0, nil
 	}
@@ -90,7 +91,7 @@ func (b *SimulatedBackend) HasCode(contract common.Address, pending bool) (bool,
 
 // ContractCall implements ContractCaller.ContractCall, executing the specified
 // contract with the given input data.
-func (b *SimulatedBackend) ContractCall(contract common.Address, data []byte, pending bool) ([]byte, error) {
+func (b *SimulatedBackend) ContractCall(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error) {
 	// Create a copy of the current state db to screw around with
 	var (
 		block   *types.Block
@@ -129,20 +130,20 @@ func (b *SimulatedBackend) ContractCall(contract common.Address, data []byte, pe
 
 // PendingAccountNonce implements ContractTransactor.PendingAccountNonce, retrieving
 // the nonce currently pending for the account.
-func (b *SimulatedBackend) PendingAccountNonce(account common.Address) (uint64, error) {
+func (b *SimulatedBackend) PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error) {
 	return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
 }
 
 // SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
 // chain doens't have miners, we just return a gas price of 1 for any call.
-func (b *SimulatedBackend) SuggestGasPrice() (*big.Int, error) {
+func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
 	return big.NewInt(1), nil
 }
 
 // EstimateGasLimit implements ContractTransactor.EstimateGasLimit, executing the
 // requested code against the currently pending block/state and returning the used
 // gas.
-func (b *SimulatedBackend) EstimateGasLimit(sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
+func (b *SimulatedBackend) EstimateGasLimit(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
 	// Create a copy of the currently pending state db to screw around with
 	var (
 		block   = b.pendingBlock
@@ -177,7 +178,7 @@ func (b *SimulatedBackend) EstimateGasLimit(sender common.Address, contract *com
 
 // SendTransaction implements ContractTransactor.SendTransaction, delegating the raw
 // transaction injection to the remote node.
-func (b *SimulatedBackend) SendTransaction(tx *types.Transaction) error {
+func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
 	blocks, _ := core.GenerateChain(b.blockchain.CurrentBlock(), b.database, 1, func(number int, block *core.BlockGen) {
 		for _, tx := range b.pendingBlock.Transactions() {
 			block.AddTx(tx)
diff --git a/accounts/abi/bind/base.go b/accounts/abi/bind/base.go
index 75e8d5bc8..80948d3f1 100644
--- a/accounts/abi/bind/base.go
+++ b/accounts/abi/bind/base.go
@@ -26,6 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"golang.org/x/net/context"
 )
 
 // SignerFn is a signer function callback when a contract requires a method to
@@ -35,6 +36,8 @@ type SignerFn func(common.Address, *types.Transaction) (*types.Transaction, erro
 // 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
+
+	Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
 }
 
 // TransactOpts is the collection of authorization data required to create a
@@ -47,6 +50,8 @@ type TransactOpts struct {
 	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%)
+
+	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
@@ -102,7 +107,7 @@ func (c *BoundContract) Call(opts *CallOpts, result interface{}, method string,
 	}
 	// Make sure we have a contract to operate on, and bail out otherwise
 	if (opts.Pending && atomic.LoadUint32(&c.pendingHasCode) == 0) || (!opts.Pending && atomic.LoadUint32(&c.latestHasCode) == 0) {
-		if code, err := c.caller.HasCode(c.address, opts.Pending); err != nil {
+		if code, err := c.caller.HasCode(opts.Context, c.address, opts.Pending); err != nil {
 			return err
 		} else if !code {
 			return ErrNoCode
@@ -118,7 +123,7 @@ func (c *BoundContract) Call(opts *CallOpts, result interface{}, method string,
 	if err != nil {
 		return err
 	}
-	output, err := c.caller.ContractCall(c.address, input, opts.Pending)
+	output, err := c.caller.ContractCall(opts.Context, c.address, input, opts.Pending)
 	if err != nil {
 		return err
 	}
@@ -153,7 +158,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 	}
 	nonce := uint64(0)
 	if opts.Nonce == nil {
-		nonce, err = c.transactor.PendingAccountNonce(opts.From)
+		nonce, err = c.transactor.PendingAccountNonce(opts.Context, opts.From)
 		if err != nil {
 			return nil, fmt.Errorf("failed to retrieve account nonce: %v", err)
 		}
@@ -163,7 +168,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 	// Figure out the gas allowance and gas price values
 	gasPrice := opts.GasPrice
 	if gasPrice == nil {
-		gasPrice, err = c.transactor.SuggestGasPrice()
+		gasPrice, err = c.transactor.SuggestGasPrice(opts.Context)
 		if err != nil {
 			return nil, fmt.Errorf("failed to suggest gas price: %v", err)
 		}
@@ -172,7 +177,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 	if gasLimit == nil {
 		// Gas estimation cannot succeed without code for method invocations
 		if contract != nil && atomic.LoadUint32(&c.pendingHasCode) == 0 {
-			if code, err := c.transactor.HasCode(c.address, true); err != nil {
+			if code, err := c.transactor.HasCode(opts.Context, c.address, true); err != nil {
 				return nil, err
 			} else if !code {
 				return nil, ErrNoCode
@@ -180,7 +185,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 			atomic.StoreUint32(&c.pendingHasCode, 1)
 		}
 		// If the contract surely has code (or code is not needed), estimate the transaction
-		gasLimit, err = c.transactor.EstimateGasLimit(opts.From, contract, value, input)
+		gasLimit, err = c.transactor.EstimateGasLimit(opts.Context, opts.From, contract, value, input)
 		if err != nil {
 			return nil, fmt.Errorf("failed to exstimate gas needed: %v", err)
 		}
@@ -199,7 +204,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 	if err != nil {
 		return nil, err
 	}
-	if err := c.transactor.SendTransaction(signedTx); err != nil {
+	if err := c.transactor.SendTransaction(opts.Context, signedTx); err != nil {
 		return nil, err
 	}
 	return signedTx, nil