bring in khatru and eventstore.

eventstore/badger/lib.go

@@ -0,0 +1,100 @@
+package badger
+
+import (
+	"encoding/binary"
+	"fmt"
+	"sync/atomic"
+
+	"github.com/dgraph-io/badger/v4"
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+const (
+	dbVersionKey          byte = 255
+	rawEventStorePrefix   byte = 0
+	indexCreatedAtPrefix  byte = 1
+	indexIdPrefix         byte = 2
+	indexKindPrefix       byte = 3
+	indexPubkeyPrefix     byte = 4
+	indexPubkeyKindPrefix byte = 5
+	indexTagPrefix        byte = 6
+	indexTag32Prefix      byte = 7
+	indexTagAddrPrefix    byte = 8
+)
+
+var _ eventstore.Store = (*BadgerBackend)(nil)
+
+type BadgerBackend struct {
+	Path                  string
+	MaxLimit              int
+	MaxLimitNegentropy    int
+	BadgerOptionsModifier func(badger.Options) badger.Options
+
+	// Experimental
+	SkipIndexingTag func(event *nostr.Event, tagName string, tagValue string) bool
+	// Experimental
+	IndexLongerTag func(event *nostr.Event, tagName string, tagValue string) bool
+
+	*badger.DB
+
+	serial atomic.Uint32
+}
+
+func (b *BadgerBackend) Init() error {
+	opts := badger.DefaultOptions(b.Path)
+	if b.BadgerOptionsModifier != nil {
+		opts = b.BadgerOptionsModifier(opts)
+	}
+
+	db, err := badger.Open(opts)
+	if err != nil {
+		return err
+	}
+	b.DB = db
+
+	if err := b.runMigrations(); err != nil {
+		return fmt.Errorf("error running migrations: %w", err)
+	}
+
+	if b.MaxLimit != 0 {
+		b.MaxLimitNegentropy = b.MaxLimit
+	} else {
+		b.MaxLimit = 1000
+		if b.MaxLimitNegentropy == 0 {
+			b.MaxLimitNegentropy = 16777216
+		}
+	}
+
+	if err := b.DB.View(func(txn *badger.Txn) error {
+		it := txn.NewIterator(badger.IteratorOptions{
+			Prefix:  []byte{0},
+			Reverse: true,
+		})
+		it.Seek([]byte{1})
+		if it.Valid() {
+			key := it.Item().Key()
+			idx := key[1:]
+			serial := binary.BigEndian.Uint32(idx)
+			b.serial.Store(serial)
+		}
+		it.Close()
+		return nil
+	}); err != nil {
+		return fmt.Errorf("error initializing serial: %w", err)
+	}
+
+	return nil
+}
+
+func (b *BadgerBackend) Close() {
+	b.DB.Close()
+}
+
+func (b *BadgerBackend) Serial() []byte {
+	next := b.serial.Add(1)
+	vb := make([]byte, 5)
+	vb[0] = rawEventStorePrefix
+	binary.BigEndian.PutUint32(vb[1:], next)
+	return vb
+}