Merge pull request ethereum#2930 from fjl/ethclient

Stable Go API, part 1

accounts/abi/bind/backend.go

@@ -20,93 +20,78 @@ import (
 	"errors"
 	"math/big"
 
+	"github.com/ethereum/go-ethereum"
 	"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
-// recipient contract to operate on does not exist in the state db or does not
-// have any code associated with it (i.e. suicided).
-var ErrNoCode = errors.New("no contract code at given address")
+var (
+	// ErrNoCode is returned by call and transact operations for which the requested
+	// recipient contract to operate on does not exist in the state db or does not
+	// have any code associated with it (i.e. suicided).
+	ErrNoCode = errors.New("no contract code at given address")
+
+	// This error is raised when attempting to perform a pending state action
+	// on a backend that doesn't implement PendingContractCaller.
+	ErrNoPendingState = errors.New("backend does not support pending state")
+
+	// This error is returned by WaitDeployed if contract creation leaves an
+	// empty contract behind.
+	ErrNoCodeAfterDeploy = errors.New("no contract code after deployment")
+)
 
 // ContractCaller defines the methods needed to allow operating with contract on a read
 // only basis.
 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(ctx context.Context, contract common.Address, pending bool) (bool, error)
+	// CodeAt returns the code of the given account. This is needed to differentiate
+	// between contract internal errors and the local chain being out of sync.
+	CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error)
+	// ContractCall executes an Ethereum contract call with the specified data as the
+	// input.
+	CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, 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(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error)
+// DeployBackend wraps the operations needed by WaitMined and WaitDeployed.
+type DeployBackend interface {
+	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
+	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
+}
+
+// PendingContractCaller defines methods to perform contract calls on the pending state.
+// Call will try to discover this interface when access to the pending state is requested.
+// If the backend does not support the pending state, Call returns ErrNoPendingState.
+type PendingContractCaller interface {
+	// PendingCodeAt returns the code of the given account in the pending state.
+	PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error)
+	// PendingCallContract executes an Ethereum contract call against the pending state.
+	PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error)
 }
 
 // ContractTransactor defines the methods needed to allow operating with contract
 // on a write only basis. Beside the transacting method, the remainder are helpers
 // used when the user does not provide some needed values, but rather leaves it up
 // to the transactor to decide.
 type ContractTransactor interface {
-	// PendingAccountNonce retrieves the current pending nonce associated with an
-	// account.
-	PendingAccountNonce(ctx context.Context, account common.Address) (uint64, error)
-
+	// PendingCodeAt returns the code of the given account in the pending state.
+	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
+	// PendingNonceAt retrieves the current pending nonce associated with an account.
+	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
 	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
 	// execution of a transaction.
 	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(ctx context.Context, contract common.Address, pending bool) (bool, error)
-
-	// EstimateGasLimit tries to estimate the gas needed to execute a specific
+	// EstimateGas 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(ctx context.Context, sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error)
-
+	EstimateGas(ctx context.Context, call ethereum.CallMsg) (usedGas *big.Int, err error)
 	// SendTransaction injects the transaction into the pending pool for execution.
 	SendTransaction(ctx context.Context, tx *types.Transaction) error
 }
 
-// ContractBackend defines the methods needed to allow operating with contract
-// on a read-write basis.
-//
-// This interface is essentially the union of ContractCaller and ContractTransactor
-// but due to a bug in the Go compiler (https://github.com/golang/go/issues/6977),
-// we cannot simply list it as the two interfaces. The other solution is to add a
-// third interface containing the common methods, but that convolutes the user API
-// as it introduces yet another parameter to require for initialization.
+// ContractBackend defines the methods needed to work with contracts on a read-write basis.
 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(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(ctx context.Context, contract common.Address, data []byte, pending bool) ([]byte, error)
-
-	// PendingAccountNonce retrieves the current pending nonce associated with an
-	// account.
-	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(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(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(ctx context.Context, tx *types.Transaction) error
+	ContractCaller
+	ContractTransactor
 }