Handle wallet initialization

StartWallet was called before service initialization.
After the recent changes this call was moved after initialization, but
the geth system automatically start services.
This meant that `IsStarted()` returned true, although the reactor was
not started, and only after calling `StopWallet()` and `StartWallet()`
again the system would reach the right state.

This commit changes the behavior so that we only check whether the
reactor has been started when calling `IsStarted()` and we allow
multiple calls to `Start()` on the signal service, which won't return an
error (it's a noop if callled multiple times).

VERSION

@@ -1 +1 @@
-0.56.8
+0.56.9

services/wallet/service.go

@@ -32,6 +32,7 @@ type Service struct {
 	reactor *Reactor
 	signals *SignalsTransmitter
 	client  *ethclient.Client
+	started bool
 
 	group        *Group
 	accountsFeed *event.Feed
@@ -55,6 +56,7 @@ func (s *Service) StartReactor(client *ethclient.Client, accounts []common.Addre
 	s.group.Add(func(ctx context.Context) error {
 		return WatchAccountsChanges(ctx, s.accountsFeed, accounts, reactor)
 	})
+	s.started = true
 	return nil
 }
 
@@ -68,6 +70,7 @@ func (s *Service) StopReactor() error {
 		s.group.Stop()
 		s.group.Wait()
 	}
+	s.started = false
 	return nil
 }
 
@@ -153,5 +156,5 @@ func mapToList(m map[common.Address]struct{}) []common.Address {
 }
 
 func (s *Service) IsStarted() bool {
-	return s.group != nil
+	return s.started
 }

services/wallet/transmitter.go

@@ -24,7 +24,8 @@ type SignalsTransmitter struct {
 // Start runs loop in background.
 func (tmr *SignalsTransmitter) Start() error {
 	if tmr.quit != nil {
-		return errAlreadyRunning
+		// already running, nothing to do
+		return nil
 	}
 	tmr.quit = make(chan struct{})
 	events := make(chan Event, 10)