// 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 (
"encoding/json"
"errors"
"math/big"
"reflect"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
)
// ErrUnknownAccount is returned for any requested operation for which no backend
// provides the specified account.
var ErrUnknownAccount = errors.New("unknown account")
// ErrNotSupported is returned when an operation is requested from an account
// backend that it does not support.
var ErrNotSupported = errors.New("not supported")
// Account represents a stored key.
// When used as an argument, it selects a unique key to act on.
type Account struct {
Address common.Address // Ethereum account address derived from the key
URL string // Optional resource locator within a backend
backend Backend // Backend where this account originates from
}
func (acc *Account) MarshalJSON() ([]byte, error) {
return []byte(`"` + acc.Address.Hex() + `"`), nil
}
func (acc *Account) UnmarshalJSON(raw []byte) error {
return json.Unmarshal(raw, &acc.Address)
}
// Manager is an overarching account manager that can communicate with various
// backends for signing transactions.
type Manager struct {
backends []Backend // List of currently registered backends (ordered by registration)
index map[reflect.Type]Backend // Set of currently registered backends
lock sync.RWMutex
}
// NewManager creates a generic account manager to sign transaction via various
// supported backends.
func NewManager(backends ...Backend) *Manager {
am := &Manager{
backends: backends,
index: make(map[reflect.Type]Backend),
}
for _, backend := range backends {
am.index[reflect.TypeOf(backend)] = backend
}
return am
}
// Backend retrieves the backend with the given type from the account manager.
func (am *Manager) Backend(backend reflect.Type) Backend {
return am.index[backend]
}
// Accounts returns all signer accounts registered under this account manager.
func (am *Manager) Accounts() []Account {
am.lock.RLock()
defer am.lock.RUnlock()
var all []Account
for _, backend := range am.backends { // TODO(karalabe): cache these after subscriptions are in
accounts := backend.Accounts()
for i := 0; i < len(accounts); i++ {
accounts[i].backend = backend
}
all = append(all, accounts...)
}
return all
}
// HasAddress reports whether a key with the given address is present.
func (am *Manager) HasAddress(addr common.Address) bool {
am.lock.RLock()
defer am.lock.RUnlock()
for _, backend := range am.backends {
if backend.HasAddress(addr) {
return true
}
}
return false
}
// SignHash requests the account manager to get the hash signed with an arbitrary
// signing backend holding the authorization for the specified account.
func (am *Manager) SignHash(acc Account, hash []byte) ([]byte, error) {
am.lock.RLock()
defer am.lock.RUnlock()
if err := am.ensureBackend(&acc); err != nil {
return nil, err
}
return acc.backend.SignHash(acc, hash)
}
// SignTx requests the account manager to get the transaction signed with an
// arbitrary signing backend holding the authorization for the specified account.
func (am *Manager) SignTx(acc Account, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
am.lock.RLock()
defer am.lock.RUnlock()
if err := am.ensureBackend(&acc); err != nil {
return nil, err
}
return acc.backend.SignTx(acc, tx, chainID)
}
// SignHashWithPassphrase requests the account manager to get the hash signed with
// an arbitrary signing backend holding the authorization for the specified account.
func (am *Manager) SignHashWithPassphrase(acc Account, passphrase string, hash []byte) ([]byte, error) {
am.lock.RLock()
defer am.lock.RUnlock()
if err := am.ensureBackend(&acc); err != nil {
return nil, err
}
return acc.backend.SignHashWithPassphrase(acc, passphrase, hash)
}
// SignTxWithPassphrase requests the account manager to get the transaction signed
// with an arbitrary signing backend holding the authorization for the specified
// account.
func (am *Manager) SignTxWithPassphrase(acc Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
am.lock.RLock()
defer am.lock.RUnlock()
if err := am.ensureBackend(&acc); err != nil {
return nil, err
}
return acc.backend.SignTxWithPassphrase(acc, passphrase, tx, chainID)
}
// ensureBackend ensures that the account has a correctly set backend and that
// it is still alive.
//
// Please note, this method assumes the manager lock is held!
func (am *Manager) ensureBackend(acc *Account) error {
// If we have a backend, make sure it's still live
if acc.backend != nil {
if _, exists := am.index[reflect.TypeOf(acc.backend)]; !exists {
return ErrUnknownAccount
}
return nil
}
// If we don't have a known backend, look up one that can service it
for _, backend := range am.backends {
if backend.HasAddress(acc.Address) { // TODO(karalabe): this assumes unique addresses per backend
acc.backend = backend
return nil
}
}
return ErrUnknownAccount
}
