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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package accounts implements high level Ethereum account management.
package accounts
import (
"math/big"
ethereum "github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/event"
)
// Account represents an Ethereum account located at a specific location defined
// by the optional URL field.
type Account struct {
Address common.Address `json:"address"` // Ethereum account address derived from the key
URL URL `json:"url"` // Optional resource locator within a backend
}
// Wallet represents a software or hardware wallet that might contain one or more
// accounts (derived from the same seed).
type Wallet interface {
// URL retrieves the canonical path under which this wallet is reachable. It is
// user by upper layers to define a sorting order over all wallets from multiple
// backends.
URL() URL
// Status returns a textual status to aid the user in the current state of the
// wallet. It also returns an error indicating any failure the wallet might have
// encountered.
Status() (string, error)
// Open initializes access to a wallet instance. It is not meant to unlock or
// decrypt account keys, rather simply to establish a connection to hardware
// wallets and/or to access derivation seeds.
//
// The passphrase parameter may or may not be used by the implementation of a
// particular wallet instance. The reason there is no passwordless open method
// is to strive towards a uniform wallet handling, oblivious to the different
// backend providers.
//
// Please note, if you open a wallet, you must close it to release any allocated
// resources (especially important when working with hardware wallets).
Open(passphrase string) error
// Close releases any resources held by an open wallet instance.
Close() error
// Accounts retrieves the list of signing accounts the wallet is currently aware
// of. For hierarchical deterministic wallets, the list will not be exhaustive,
// rather only contain the accounts explicitly pinned during account derivation.
Accounts() []Account
// Contains returns whether an account is part of this particular wallet or not.
Contains(account Account) bool
// Derive attempts to explicitly derive a hierarchical deterministic account at
// the specified derivation path. If requested, the derived account will be added
// to the wallet's tracked account list.
Derive(path DerivationPath, pin bool) (Account, error)
// SelfDerive sets a base account derivation path from which the wallet attempts
// to discover non zero accounts and automatically add them to list of tracked
// accounts.
//
// Note, self derivaton will increment the last component of the specified path
// opposed to decending into a child path to allow discovering accounts starting
// from non zero components.
//
// You can disable automatic account discovery by calling SelfDerive with a nil
// chain state reader.
SelfDerive(base DerivationPath, chain ethereum.ChainStateReader)
// SignHash requests the wallet to sign the given hash.
//
// It looks up the account specified either solely via its address contained within,
// or optionally with the aid of any location metadata from the embedded URL field.
//
// If the wallet requires additional authentication to sign the request (e.g.
// a password to decrypt the account, or a PIN code o verify the transaction),
// an AuthNeededError instance will be returned, containing infos for the user
// about which fields or actions are needed. The user may retry by providing
// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock
// the account in a keystore).
SignHash(account Account, hash []byte) ([]byte, error)
// SignTx requests the wallet to sign the given transaction.
//
// It looks up the account specified either solely via its address contained within,
// or optionally with the aid of any location metadata from the embedded URL field.
//
// If the wallet requires additional authentication to sign the request (e.g.
// a password to decrypt the account, or a PIN code o verify the transaction),
// an AuthNeededError instance will be returned, containing infos for the user
// about which fields or actions are needed. The user may retry by providing
// the needed details via SignTxWithPassphrase, or by other means (e.g. unlock
// the account in a keystore).
SignTx(account Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error)
// SignHashWithPassphrase requests the wallet to sign the given hash with the
// given passphrase as extra authentication information.
//
// It looks up the account specified either solely via its address contained within,
// or optionally with the aid of any location metadata from the embedded URL field.
SignHashWithPassphrase(account Account, passphrase string, hash []byte) ([]byte, error)
// SignTxWithPassphrase requests the wallet to sign the given transaction, with the
// given passphrase as extra authentication information.
//
// It looks up the account specified either solely via its address contained within,
// or optionally with the aid of any location metadata from the embedded URL field.
SignTxWithPassphrase(account Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error)
}
// Backend is a "wallet provider" that may contain a batch of accounts they can
// sign transactions with and upon request, do so.
type Backend interface {
// Wallets retrieves the list of wallets the backend is currently aware of.
//
// The returned wallets are not opened by default. For software HD wallets this
// means that no base seeds are decrypted, and for hardware wallets that no actual
// connection is established.
//
// The resulting wallet list will be sorted alphabetically based on its internal
// URL assigned by the backend. Since wallets (especially hardware) may come and
// go, the same wallet might appear at a different positions in the list during
// subsequent retrievals.
Wallets() []Wallet
// Subscribe creates an async subscription to receive notifications when the
// backend detects the arrival or departure of a wallet.
Subscribe(sink chan<- WalletEvent) event.Subscription
}
// WalletEventType represents the different event types that can be fired by
// the wallet subscription subsystem.
type WalletEventType int
const (
// WalletArrived is fired when a new wallet is detected either via USB or via
// a filesystem event in the keystore.
WalletArrived WalletEventType = iota
// WalletOpened is fired when a wallet is successfully opened with the purpose
// of starting any background processes such as automatic key derivation.
WalletOpened
// WalletDropped
WalletDropped
)
// WalletEvent is an event fired by an account backend when a wallet arrival or
// departure is detected.
type WalletEvent struct {
Wallet Wallet // Wallet instance arrived or departed
Kind WalletEventType // Event type that happened in the system
}
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