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// Copyright 2021 The Swarm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package epochs
import (
"context"
"github.com/ethersphere/bee/pkg/crypto"
"github.com/ethersphere/bee/pkg/feeds"
"github.com/ethersphere/bee/pkg/storage"
)
var _ feeds.Updater = (*updater)(nil)
// Updater encapsulates a feeds putter to generate successive updates for epoch based feeds
// it persists the last update
type updater struct {
*feeds.Putter
last int64
epoch feeds.Index
}
// NewUpdater constructs a feed updater
func NewUpdater(putter storage.Putter, signer crypto.Signer, topic []byte) (feeds.Updater, error) {
p, err := feeds.NewPutter(putter, signer, topic)
if err != nil {
return nil, err
}
return &updater{Putter: p}, nil
}
// Update pushes an update to the feed through the chunk stores
func (u *updater) Update(ctx context.Context, at int64, payload []byte) error {
e := next(u.epoch, u.last, uint64(at))
err := u.Put(ctx, e, at, payload)
if err != nil {
return err
}
u.last = at
u.epoch = e
return nil
}
func (u *updater) Feed() *feeds.Feed {
return u.Putter.Feed
}