96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
package lmdb
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import (
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"bytes"
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"context"
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"encoding/binary"
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"github.com/PowerDNS/lmdb-go/lmdb"
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"github.com/nbd-wtf/go-nostr"
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nostr_binary "github.com/nbd-wtf/go-nostr/binary"
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)
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func (b *LMDBBackend) CountEvents(ctx context.Context, filter nostr.Filter) (int64, error) {
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var count int64 = 0
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queries, extraFilter, since, err := b.prepareQueries(filter)
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if err != nil {
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return 0, err
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}
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err = b.lmdbEnv.View(func(txn *lmdb.Txn) error {
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// actually iterate
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for _, q := range queries {
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cursor, err := txn.OpenCursor(q.dbi)
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if err != nil {
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continue
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}
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var k []byte
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var idx []byte
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var iterr error
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if _, _, errsr := cursor.Get(q.startingPoint, nil, lmdb.SetRange); errsr != nil {
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if operr, ok := errsr.(*lmdb.OpError); !ok || operr.Errno != lmdb.NotFound {
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// in this case it's really an error
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panic(err)
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} else {
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// we're at the end and we just want notes before this,
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// so we just need to set the cursor the last key, this is not a real error
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k, idx, iterr = cursor.Get(nil, nil, lmdb.Last)
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}
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} else {
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// move one back as the first step
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k, idx, iterr = cursor.Get(nil, nil, lmdb.Prev)
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}
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for {
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// we already have a k and a v and an err from the cursor setup, so check and use these
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if iterr != nil ||
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len(k) != q.prefixSize+q.timestampSize ||
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!bytes.Equal(k[:q.prefixSize], q.prefix) {
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// either iteration has errored or we reached the end of this prefix
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break // stop this cursor and move to the next one
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}
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// "id" indexes don't contain a timestamp
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if q.timestampSize == 4 {
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createdAt := binary.BigEndian.Uint32(k[len(k)-4:])
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if createdAt < since {
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break
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}
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}
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if extraFilter == nil {
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count++
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} else {
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// fetch actual event
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val, err := txn.Get(b.rawEventStore, idx)
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if err != nil {
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panic(err)
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}
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evt := &nostr.Event{}
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if err := nostr_binary.Unmarshal(val, evt); err != nil {
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return err
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}
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// check if this matches the other filters that were not part of the index
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if extraFilter.Matches(evt) {
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count++
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}
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return nil
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}
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// move one back (we'll look into k and v and err in the next iteration)
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k, idx, iterr = cursor.Get(nil, nil, lmdb.Prev)
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}
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}
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return nil
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})
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return count, err
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}
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