plugeth/event/multisub.go

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// Copyright 2023 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 event
// JoinSubscriptions joins multiple subscriptions to be able to track them as
// one entity and collectively cancel them of consume any errors from them.
func JoinSubscriptions(subs ...Subscription) Subscription {
return NewSubscription(func(unsubbed <-chan struct{}) error {
// Unsubscribe all subscriptions before returning
defer func() {
for _, sub := range subs {
sub.Unsubscribe()
}
}()
// Wait for an error on any of the subscriptions and propagate up
errc := make(chan error, len(subs))
for i := range subs {
go func(sub Subscription) {
select {
case err := <-sub.Err():
if err != nil {
errc <- err
}
case <-unsubbed:
}
}(subs[i])
}
select {
case err := <-errc:
return err
case <-unsubbed:
return nil
}
})
}