status-go/services/wallet/walletevent/watcher.go

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package walletevent
import (
"context"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/status-im/status-go/services/wallet/async"
)
type EventCb func(event Event)
// Watcher executes a given callback whenever a wallet event gets sent
type Watcher struct {
feed *event.Feed
group *async.Group
callback EventCb
}
func NewWatcher(feed *event.Feed, callback EventCb) *Watcher {
return &Watcher{
feed: feed,
callback: callback,
}
}
func (w *Watcher) Start() {
if w.group != nil {
return
}
w.group = async.NewGroup(context.Background())
w.group.Add(func(ctx context.Context) error {
return watch(ctx, w.feed, w.callback)
})
}
func (w *Watcher) Stop() {
if w.group != nil {
w.group.Stop()
w.group.Wait()
w.group = nil
}
}
func watch(ctx context.Context, feed *event.Feed, callback EventCb) error {
ch := make(chan Event, 10)
sub := feed.Subscribe(ch)
defer sub.Unsubscribe()
for {
select {
case <-ctx.Done():
return nil
case err := <-sub.Err():
if err != nil {
log.Error("wallet event watcher subscription failed", "error", err)
}
case ev := <-ch:
if callback != nil {
callback(ev)
}
}
}
}