111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
package dedup
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import (
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"time"
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"github.com/status-im/status-go/db"
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whisper "github.com/status-im/whisper/whisperv6"
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"github.com/syndtr/goleveldb/leveldb"
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"github.com/syndtr/goleveldb/leveldb/util"
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"golang.org/x/crypto/sha3"
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)
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// cache represents a cache of whisper messages with a limit of 2 days.
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// the limit is counted from the time when the message was added to the cache.
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type cache struct {
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db *leveldb.DB
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now func() time.Time
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}
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func newCache(db *leveldb.DB) *cache {
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return &cache{db, time.Now}
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}
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func (d *cache) Has(filterID string, message *whisper.Message) (bool, error) {
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has, err := d.db.Has(d.keyToday(filterID, message), nil)
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if err != nil {
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return false, err
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}
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if has {
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return true, nil
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}
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return d.db.Has(d.keyYesterday(filterID, message), nil)
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}
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func (d *cache) Put(filterID string, messages []*whisper.Message) error {
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batch := leveldb.Batch{}
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for _, msg := range messages {
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batch.Put(d.keyToday(filterID, msg), []byte{})
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}
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err := d.db.Write(&batch, nil)
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if err != nil {
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return err
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}
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return d.cleanOldEntries()
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}
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func (d *cache) cleanOldEntries() error {
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// Cleaning up everything that is older than 2 days
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// We are using the fact that leveldb can do prefix queries and that
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// the entries are sorted by keys.
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// Here, we are looking for all the keys that are between
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// 00000000.* and <yesterday's date>.*
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// e.g. (0000000.* -> 20180424.*)
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limit := d.yesterdayDateString()
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r := &util.Range{
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Start: db.Key(db.DeduplicatorCache, []byte("00000000")),
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Limit: db.Key(db.DeduplicatorCache, []byte(limit)),
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}
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batch := leveldb.Batch{}
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iter := d.db.NewIterator(r, nil)
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for iter.Next() {
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batch.Delete(iter.Key())
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}
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iter.Release()
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return d.db.Write(&batch, nil)
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}
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func (d *cache) keyYesterday(filterID string, message *whisper.Message) []byte {
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return prefixedKey(d.yesterdayDateString(), filterID, message)
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}
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func (d *cache) keyToday(filterID string, message *whisper.Message) []byte {
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return prefixedKey(d.todayDateString(), filterID, message)
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}
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func (d *cache) todayDateString() string {
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return dateString(d.now())
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}
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func (d *cache) yesterdayDateString() string {
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now := d.now()
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yesterday := now.Add(-24 * time.Hour)
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return dateString(yesterday)
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}
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func dateString(t time.Time) string {
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// Layouts must use the reference time Mon Jan 2 15:04:05 MST 2006
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return t.Format("20060102")
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}
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func prefixedKey(date, filterID string, message *whisper.Message) []byte {
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return db.Key(db.DeduplicatorCache, []byte(date), []byte(filterID), key(message))
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}
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func key(message *whisper.Message) []byte {
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data := make([]byte, len(message.Payload)+len(message.Topic))
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copy(data[:], message.Payload)
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copy(data[len(message.Payload):], message.Topic[:])
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digest := sha3.Sum512(data)
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return digest[:]
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}
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