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-rw-r--r--accounts/manager.go194
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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
+
+import (
+ "reflect"
+ "sort"
+ "sync"
+
+ "github.com/ethereum/go-ethereum/event"
+)
+
+// Manager is an overarching account manager that can communicate with various
+// backends for signing transactions.
+type Manager struct {
+ backends map[reflect.Type][]Backend // Index of backends currently registered
+ updaters []event.Subscription // Wallet update subscriptions for all backends
+ updates chan WalletEvent // Subscription sink for backend wallet changes
+ wallets []Wallet // Cache of all wallets from all registered backends
+
+ feed event.Feed // Wallet feed notifying of arrivals/departures
+
+ quit chan chan error
+ lock sync.RWMutex
+}
+
+// NewManager creates a generic account manager to sign transaction via various
+// supported backends.
+func NewManager(backends ...Backend) *Manager {
+ // Subscribe to wallet notifications from all backends
+ updates := make(chan WalletEvent, 4*len(backends))
+
+ subs := make([]event.Subscription, len(backends))
+ for i, backend := range backends {
+ subs[i] = backend.Subscribe(updates)
+ }
+ // Retrieve the initial list of wallets from the backends and sort by URL
+ var wallets []Wallet
+ for _, backend := range backends {
+ wallets = merge(wallets, backend.Wallets()...)
+ }
+ // Assemble the account manager and return
+ am := &Manager{
+ backends: make(map[reflect.Type][]Backend),
+ updaters: subs,
+ updates: updates,
+ wallets: wallets,
+ quit: make(chan chan error),
+ }
+ for _, backend := range backends {
+ kind := reflect.TypeOf(backend)
+ am.backends[kind] = append(am.backends[kind], backend)
+ }
+ go am.update()
+
+ return am
+}
+
+// Close terminates the account manager's internal notification processes.
+func (am *Manager) Close() error {
+ errc := make(chan error)
+ am.quit <- errc
+ return <-errc
+}
+
+// update is the wallet event loop listening for notifications from the backends
+// and updating the cache of wallets.
+func (am *Manager) update() {
+ // Close all subscriptions when the manager terminates
+ defer func() {
+ am.lock.Lock()
+ for _, sub := range am.updaters {
+ sub.Unsubscribe()
+ }
+ am.updaters = nil
+ am.lock.Unlock()
+ }()
+
+ // Loop until termination
+ for {
+ select {
+ case event := <-am.updates:
+ // Wallet event arrived, update local cache
+ am.lock.Lock()
+ if event.Arrive {
+ am.wallets = merge(am.wallets, event.Wallet)
+ } else {
+ am.wallets = drop(am.wallets, event.Wallet)
+ }
+ am.lock.Unlock()
+
+ // Notify any listeners of the event
+ am.feed.Send(event)
+
+ case errc := <-am.quit:
+ // Manager terminating, return
+ errc <- nil
+ return
+ }
+ }
+}
+
+// Backends retrieves the backend(s) with the given type from the account manager.
+func (am *Manager) Backends(kind reflect.Type) []Backend {
+ return am.backends[kind]
+}
+
+// Wallets returns all signer accounts registered under this account manager.
+func (am *Manager) Wallets() []Wallet {
+ am.lock.RLock()
+ defer am.lock.RUnlock()
+
+ cpy := make([]Wallet, len(am.wallets))
+ copy(cpy, am.wallets)
+ return cpy
+}
+
+// Wallet retrieves the wallet associated with a particular URL.
+func (am *Manager) Wallet(url string) (Wallet, error) {
+ am.lock.RLock()
+ defer am.lock.RUnlock()
+
+ for _, wallet := range am.Wallets() {
+ if wallet.URL() == url {
+ return wallet, nil
+ }
+ }
+ return nil, ErrUnknownWallet
+}
+
+// Find attempts to locate the wallet corresponding to a specific account. Since
+// accounts can be dynamically added to and removed from wallets, this method has
+// a linear runtime in the number of wallets.
+func (am *Manager) Find(account Account) (Wallet, error) {
+ am.lock.RLock()
+ defer am.lock.RUnlock()
+
+ for _, wallet := range am.wallets {
+ if wallet.Contains(account) {
+ return wallet, nil
+ }
+ }
+ return nil, ErrUnknownAccount
+}
+
+// Subscribe creates an async subscription to receive notifications when the
+// manager detects the arrival or departure of a wallet from any of its backends.
+func (am *Manager) Subscribe(sink chan<- WalletEvent) event.Subscription {
+ return am.feed.Subscribe(sink)
+}
+
+// merge is a sorted analogue of append for wallets, where the ordering of the
+// origin list is preserved by inserting new wallets at the correct position.
+//
+// The original slice is assumed to be already sorted by URL.
+func merge(slice []Wallet, wallets ...Wallet) []Wallet {
+ for _, wallet := range wallets {
+ n := sort.Search(len(slice), func(i int) bool { return slice[i].URL() >= wallet.URL() })
+ if n == len(slice) {
+ slice = append(slice, wallet)
+ continue
+ }
+ slice = append(slice[:n], append([]Wallet{wallet}, slice[n:]...)...)
+ }
+ return slice
+}
+
+// drop is the couterpart of merge, which looks up wallets from within the sorted
+// cache and removes the ones specified.
+func drop(slice []Wallet, wallets ...Wallet) []Wallet {
+ for _, wallet := range wallets {
+ n := sort.Search(len(slice), func(i int) bool { return slice[i].URL() >= wallet.URL() })
+ if n == len(slice) {
+ // Wallet not found, may happen during startup
+ continue
+ }
+ slice = append(slice[:n], slice[n+1:]...)
+ }
+ return slice
+}