boltdb support.

bolt/helpers.go

@@ -0,0 +1,114 @@
+package bolt
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/nbd-wtf/go-nostr"
+	"golang.org/x/exp/slices"
+)
+
+// returns
+// - the bucket id where this will be saved
+// - the key with full length for created_at and idx at the end, but not filled with these
+// - the offset -- i.e. where the prefix ends and the created_at and idx would start
+func getTagIndexPrefix(tagValue string) (bucket []byte, key []byte, offset int) {
+	if kind, pkb, d := eventstore.GetAddrTagElements(tagValue); len(pkb) == 32 {
+		// store value in the new special "a" tag index
+		key = make([]byte, 2+8+len(d)+4)
+		binary.BigEndian.PutUint16(key[1:], kind)
+		copy(key[2:], pkb[0:8])
+		copy(key[2+8:], d)
+		offset = 2 + 8 + len(d)
+		bucket = bucketTagAddr
+	} else if vb, _ := hex.DecodeString(tagValue); len(vb) == 32 {
+		// store value as bytes
+		key = make([]byte, 8+4)
+		copy(key, vb[0:8])
+		offset = 8
+		bucket = bucketTag32
+	} else {
+		// store whatever as utf-8
+		key = make([]byte, len(tagValue)+4)
+		copy(key, tagValue)
+		offset = len(tagValue)
+		bucket = bucketTag
+	}
+
+	return bucket, key, offset
+}
+
+type keymeta struct {
+	bucket []byte
+	key    []byte
+}
+
+func getIndexKeysForEvent(evt *nostr.Event) []keymeta {
+	keys := make([]keymeta, 0, 24)
+
+	// indexes
+	{
+		// ~ by id
+		idPrefix8, _ := hex.DecodeString(evt.ID[0 : 8*2])
+		k := idPrefix8
+		keys = append(keys, keymeta{bucket: bucketId, key: k})
+	}
+
+	{
+		// ~ by pubkey+date
+		pubkeyPrefix8, _ := hex.DecodeString(evt.PubKey[0 : 8*2])
+		k := make([]byte, 8+4)
+		copy(k[:], pubkeyPrefix8)
+		binary.BigEndian.PutUint32(k[8:], uint32(evt.CreatedAt))
+		keys = append(keys, keymeta{bucket: bucketPubkey, key: k})
+	}
+
+	{
+		// ~ by kind+date
+		k := make([]byte, 2+4)
+		binary.BigEndian.PutUint16(k[:], uint16(evt.Kind))
+		binary.BigEndian.PutUint32(k[2:], uint32(evt.CreatedAt))
+		keys = append(keys, keymeta{bucket: bucketKind, key: k})
+	}
+
+	{
+		// ~ by pubkey+kind+date
+		pubkeyPrefix8, _ := hex.DecodeString(evt.PubKey[0 : 8*2])
+		k := make([]byte, 8+2+4)
+		copy(k[:], pubkeyPrefix8)
+		binary.BigEndian.PutUint16(k[8:], uint16(evt.Kind))
+		binary.BigEndian.PutUint32(k[8+2:], uint32(evt.CreatedAt))
+		keys = append(keys, keymeta{bucket: bucketPubkeyKind, key: k})
+	}
+
+	// ~ by tagvalue+date
+	for i, tag := range evt.Tags {
+		if len(tag) < 2 || len(tag[0]) != 1 || len(tag[1]) == 0 || len(tag[1]) > 100 {
+			// not indexable
+			continue
+		}
+		firstIndex := slices.IndexFunc(evt.Tags, func(t nostr.Tag) bool { return len(t) >= 2 && t[1] == tag[1] })
+		if firstIndex != i {
+			// duplicate
+			continue
+		}
+
+		// get key prefix (with full length) and offset where to write the created_at
+		bucket, k, offset := getTagIndexPrefix(tag[1])
+
+		// write the created_at
+		binary.BigEndian.PutUint32(k[offset:], uint32(evt.CreatedAt))
+
+		keys = append(keys, keymeta{bucket: bucket, key: k})
+	}
+
+	{
+		// ~ by date only
+		k := make([]byte, 4)
+		binary.BigEndian.PutUint32(k[:], uint32(evt.CreatedAt))
+		keys = append(keys, keymeta{bucket: bucketCreatedAt, key: k})
+	}
+
+	return keys
+}