bring in khatru and eventstore.

eventstore/badger/delete.go

@@ -0,0 +1,72 @@
+package badger
+
+import (
+	"context"
+	"encoding/hex"
+	"log"
+
+	"github.com/dgraph-io/badger/v4"
+	"github.com/nbd-wtf/go-nostr"
+)
+
+var serialDelete uint32 = 0
+
+func (b *BadgerBackend) DeleteEvent(ctx context.Context, evt *nostr.Event) error {
+	deletionHappened := false
+
+	err := b.Update(func(txn *badger.Txn) error {
+		var err error
+		deletionHappened, err = b.delete(txn, evt)
+		return err
+	})
+	if err != nil {
+		return err
+	}
+
+	// after deleting, run garbage collector (sometimes)
+	if deletionHappened {
+		serialDelete = (serialDelete + 1) % 256
+		if serialDelete == 0 {
+			if err := b.RunValueLogGC(0.8); err != nil && err != badger.ErrNoRewrite {
+				log.Println("badger gc errored:" + err.Error())
+			}
+		}
+	}
+
+	return nil
+}
+
+func (b *BadgerBackend) delete(txn *badger.Txn, evt *nostr.Event) (bool, error) {
+	idx := make([]byte, 1, 5)
+	idx[0] = rawEventStorePrefix
+
+	// query event by id to get its idx
+	idPrefix8, _ := hex.DecodeString(evt.ID[0 : 8*2])
+	prefix := make([]byte, 1+8)
+	prefix[0] = indexIdPrefix
+	copy(prefix[1:], idPrefix8)
+	opts := badger.IteratorOptions{
+		PrefetchValues: false,
+	}
+	it := txn.NewIterator(opts)
+	it.Seek(prefix)
+	if it.ValidForPrefix(prefix) {
+		idx = append(idx, it.Item().Key()[1+8:]...)
+	}
+	it.Close()
+
+	// if no idx was found, end here, this event doesn't exist
+	if len(idx) == 1 {
+		return false, nil
+	}
+
+	// calculate all index keys we have for this event and delete them
+	for k := range b.getIndexKeysForEvent(evt, idx[1:]) {
+		if err := txn.Delete(k); err != nil {
+			return false, err
+		}
+	}
+
+	// delete the raw event
+	return true, txn.Delete(idx)
+}