c213fd1fd8
There is no need to depend on the old context package now that the minimum Go version is 1.7. The move to "context" eliminates our weird vendoring setup. Some vendored code still uses golang.org/x/net/context and it is now vendored in the normal way. This change triggered new vet checks around context.WithTimeout which didn't fire with golang.org/x/net/context.
211 lines
10 KiB
Go
211 lines
10 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package ethereum defines interfaces for interacting with Ethereum.
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package ethereum
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import (
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"context"
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"errors"
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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)
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// NotFound is returned by API methods if the requested item does not exist.
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var NotFound = errors.New("not found")
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// TODO: move subscription to package event
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// Subscription represents an event subscription where events are
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// delivered on a data channel.
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type Subscription interface {
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// Unsubscribe cancels the sending of events to the data channel
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// and closes the error channel.
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Unsubscribe()
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// Err returns the subscription error channel. The error channel receives
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// a value if there is an issue with the subscription (e.g. the network connection
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// delivering the events has been closed). Only one value will ever be sent.
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// The error channel is closed by Unsubscribe.
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Err() <-chan error
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}
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// ChainReader provides access to the blockchain. The methods in this interface access raw
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// data from either the canonical chain (when requesting by block number) or any
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// blockchain fork that was previously downloaded and processed by the node. The block
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// number argument can be nil to select the latest canonical block. Reading block headers
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// should be preferred over full blocks whenever possible.
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//
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// The returned error is NotFound if the requested item does not exist.
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type ChainReader interface {
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BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
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BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
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HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
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HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
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TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
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TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)
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// This method subscribes to notifications about changes of the head block of
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// the canonical chain.
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SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
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}
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// TransactionReader provides access to past transactions and their receipts.
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// Implementations may impose arbitrary restrictions on the transactions and receipts that
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// can be retrieved. Historic transactions may not be available.
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//
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// Avoid relying on this interface if possible. Contract logs (through the LogFilterer
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// interface) are more reliable and usually safer in the presence of chain
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// reorganisations.
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//
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// The returned error is NotFound if the requested item does not exist.
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type TransactionReader interface {
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// TransactionByHash checks the pool of pending transactions in addition to the
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// blockchain. The isPending return value indicates whether the transaction has been
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// mined yet. Note that the transaction may not be part of the canonical chain even if
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// it's not pending.
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TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
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// TransactionReceipt returns the receipt of a mined transaction. Note that the
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// transaction may not be included in the current canonical chain even if a receipt
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// exists.
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TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
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}
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// ChainStateReader wraps access to the state trie of the canonical blockchain. Note that
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// implementations of the interface may be unable to return state values for old blocks.
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// In many cases, using CallContract can be preferable to reading raw contract storage.
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type ChainStateReader interface {
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BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
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StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
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CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
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NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
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}
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// SyncProgress gives progress indications when the node is synchronising with
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// the Ethereum network.
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type SyncProgress struct {
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StartingBlock uint64 // Block number where sync began
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CurrentBlock uint64 // Current block number where sync is at
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HighestBlock uint64 // Highest alleged block number in the chain
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PulledStates uint64 // Number of state trie entries already downloaded
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KnownStates uint64 // Total number os state trie entries known about
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}
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// ChainSyncReader wraps access to the node's current sync status. If there's no
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// sync currently running, it returns nil.
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type ChainSyncReader interface {
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SyncProgress(ctx context.Context) (*SyncProgress, error)
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}
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// CallMsg contains parameters for contract calls.
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type CallMsg struct {
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From common.Address // the sender of the 'transaction'
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To *common.Address // the destination contract (nil for contract creation)
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Gas *big.Int // if nil, the call executes with near-infinite gas
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GasPrice *big.Int // wei <-> gas exchange ratio
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Value *big.Int // amount of wei sent along with the call
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Data []byte // input data, usually an ABI-encoded contract method invocation
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}
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// A ContractCaller provides contract calls, essentially transactions that are executed by
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// the EVM but not mined into the blockchain. ContractCall is a low-level method to
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// execute such calls. For applications which are structured around specific contracts,
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// the abigen tool provides a nicer, properly typed way to perform calls.
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type ContractCaller interface {
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CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
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}
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// FilterQuery contains options for contact log filtering.
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type FilterQuery struct {
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FromBlock *big.Int // beginning of the queried range, nil means genesis block
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ToBlock *big.Int // end of the range, nil means latest block
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Addresses []common.Address // restricts matches to events created by specific contracts
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// The Topic list restricts matches to particular event topics. Each event has a list
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// of topics. Topics matches a prefix of that list. An empty element slice matches any
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// topic. Non-empty elements represent an alternative that matches any of the
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// contained topics.
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//
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// Examples:
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// {} or nil matches any topic list
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// {{A}} matches topic A in first position
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// {{}, {B}} matches any topic in first position, B in second position
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// {{A}}, {B}} matches topic A in first position, B in second position
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// {{A, B}}, {C, D}} matches topic (A OR B) in first position, (C OR D) in second position
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Topics [][]common.Hash
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}
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// LogFilterer provides access to contract log events using a one-off query or continuous
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// event subscription.
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//
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// Logs received through a streaming query subscription may have Removed set to true,
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// indicating that the log was reverted due to a chain reorganisation.
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type LogFilterer interface {
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FilterLogs(ctx context.Context, q FilterQuery) ([]types.Log, error)
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SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- types.Log) (Subscription, error)
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}
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// TransactionSender wraps transaction sending. The SendTransaction method injects a
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// signed transaction into the pending transaction pool for execution. If the transaction
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// was a contract creation, the TransactionReceipt method can be used to retrieve the
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// contract address after the transaction has been mined.
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//
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// The transaction must be signed and have a valid nonce to be included. Consumers of the
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// API can use package accounts to maintain local private keys and need can retrieve the
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// next available nonce using PendingNonceAt.
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type TransactionSender interface {
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SendTransaction(ctx context.Context, tx *types.Transaction) error
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}
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// GasPricer wraps the gas price oracle, which monitors the blockchain to determine the
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// optimal gas price given current fee market conditions.
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type GasPricer interface {
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SuggestGasPrice(ctx context.Context) (*big.Int, error)
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}
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// A PendingStateReader provides access to the pending state, which is the result of all
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// known executable transactions which have not yet been included in the blockchain. It is
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// commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value
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// transfers) initiated by the user. The PendingNonceAt operation is a good way to
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// retrieve the next available transaction nonce for a specific account.
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type PendingStateReader interface {
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PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
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PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
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PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
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PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
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PendingTransactionCount(ctx context.Context) (uint, error)
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}
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// PendingContractCaller can be used to perform calls against the pending state.
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type PendingContractCaller interface {
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PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
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}
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// GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a
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// specific transaction based on the pending state. There is no guarantee that this is the
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// true gas limit requirement as other transactions may be added or removed by miners, but
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// it should provide a basis for setting a reasonable default.
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type GasEstimator interface {
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EstimateGas(ctx context.Context, call CallMsg) (usedGas *big.Int, err error)
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}
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// A PendingStateEventer provides access to real time notifications about changes to the
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// pending state.
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type PendingStateEventer interface {
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SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
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}
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