212 lines
10 KiB
Go
212 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 of 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 uint64 // if 0, 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 contract log filtering.
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type FilterQuery struct {
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BlockHash *common.Hash // used by eth_getLogs, return logs only from block with this hash
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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) (uint64, 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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