package dedup import ( "time" "github.com/status-im/status-go/db" whisper "github.com/status-im/whisper/whisperv6" "github.com/syndtr/goleveldb/leveldb" "github.com/syndtr/goleveldb/leveldb/util" "golang.org/x/crypto/sha3" ) // cache represents a cache of whisper messages with a limit of 2 days. // the limit is counted from the time when the message was added to the cache. type cache struct { db *leveldb.DB now func() time.Time } func newCache(db *leveldb.DB) *cache { return &cache{db, time.Now} } func (d *cache) Has(filterID string, message *whisper.Message) (bool, error) { has, err := d.db.Has(d.KeyToday(filterID, message), nil) if err != nil { return false, err } if has { return true, nil } return d.db.Has(d.keyYesterday(filterID, message), nil) } func (d *cache) Put(filterID string, messages []*whisper.Message) error { batch := leveldb.Batch{} for _, msg := range messages { batch.Put(d.KeyToday(filterID, msg), []byte{}) } err := d.db.Write(&batch, nil) if err != nil { return err } return d.cleanOldEntries() } func (d *cache) PutIDs(messageIDs [][]byte) error { batch := leveldb.Batch{} for _, id := range messageIDs { batch.Put(id, []byte{}) } err := d.db.Write(&batch, nil) if err != nil { return err } return d.cleanOldEntries() } func (d *cache) cleanOldEntries() error { // Cleaning up everything that is older than 2 days // We are using the fact that leveldb can do prefix queries and that // the entries are sorted by keys. // Here, we are looking for all the keys that are between // 00000000.* and .* // e.g. (0000000.* -> 20180424.*) limit := d.yesterdayDateString() r := &util.Range{ Start: db.Key(db.DeduplicatorCache, []byte("00000000")), Limit: db.Key(db.DeduplicatorCache, []byte(limit)), } batch := leveldb.Batch{} iter := d.db.NewIterator(r, nil) for iter.Next() { batch.Delete(iter.Key()) } iter.Release() return d.db.Write(&batch, nil) } func (d *cache) keyYesterday(filterID string, message *whisper.Message) []byte { return prefixedKey(d.yesterdayDateString(), filterID, message) } func (d *cache) KeyToday(filterID string, message *whisper.Message) []byte { return prefixedKey(d.todayDateString(), filterID, message) } func (d *cache) todayDateString() string { return dateString(d.now()) } func (d *cache) yesterdayDateString() string { now := d.now() yesterday := now.Add(-24 * time.Hour) return dateString(yesterday) } func dateString(t time.Time) string { // Layouts must use the reference time Mon Jan 2 15:04:05 MST 2006 return t.Format("20060102") } func prefixedKey(date, filterID string, message *whisper.Message) []byte { return db.Key(db.DeduplicatorCache, []byte(date), []byte(filterID), key(message)) } func key(message *whisper.Message) []byte { data := make([]byte, len(message.Payload)+len(message.Topic)) copy(data[:], message.Payload) copy(data[len(message.Payload):], message.Topic[:]) digest := sha3.Sum512(data) return digest[:] }