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next.orly.dev/pkg/database/fetch-event-by-serial.go
mleku 29e175efb0
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implement event table subtyping for small events in value log
2025-11-14 12:15:52 +00:00

104 lines
2.6 KiB
Go

package database
import (
"bytes"
"fmt"
"github.com/dgraph-io/badger/v4"
"lol.mleku.dev/chk"
"next.orly.dev/pkg/database/indexes"
"next.orly.dev/pkg/database/indexes/types"
"next.orly.dev/pkg/encoders/event"
)
func (d *D) FetchEventBySerial(ser *types.Uint40) (ev *event.E, err error) {
if err = d.View(
func(txn *badger.Txn) (err error) {
// Helper function to extract inline event data from key
extractInlineData := func(key []byte, prefixLen int) (*event.E, error) {
if len(key) > prefixLen+2 {
sizeIdx := prefixLen
size := int(key[sizeIdx])<<8 | int(key[sizeIdx+1])
dataStart := sizeIdx + 2
if len(key) >= dataStart+size {
eventData := key[dataStart : dataStart+size]
ev := new(event.E)
if err := ev.UnmarshalBinary(bytes.NewBuffer(eventData)); err != nil {
return nil, fmt.Errorf(
"error unmarshaling inline event (size=%d): %w",
size, err,
)
}
return ev, nil
}
}
return nil, nil
}
// Try sev (small event inline) prefix first - Reiser4 optimization
smallBuf := new(bytes.Buffer)
if err = indexes.SmallEventEnc(ser).MarshalWrite(smallBuf); chk.E(err) {
return
}
opts := badger.DefaultIteratorOptions
opts.Prefix = smallBuf.Bytes()
opts.PrefetchValues = true
opts.PrefetchSize = 1
it := txn.NewIterator(opts)
defer it.Close()
it.Rewind()
if it.Valid() {
// Found in sev table - extract inline data
key := it.Item().Key()
// Key format: sev|serial|size_uint16|event_data
if ev, err = extractInlineData(key, 8); err != nil {
return err
}
if ev != nil {
return nil
}
}
// Not found in sev table, try evt (traditional) prefix
buf := new(bytes.Buffer)
if err = indexes.EventEnc(ser).MarshalWrite(buf); chk.E(err) {
return
}
var item *badger.Item
if item, err = txn.Get(buf.Bytes()); err != nil {
return
}
var v []byte
if v, err = item.ValueCopy(nil); chk.E(err) {
return
}
// Check if we have valid data before attempting to unmarshal
if len(v) < 32+32+1+2+1+1+64 { // ID + Pubkey + min varint fields + Sig
err = fmt.Errorf(
"incomplete event data: got %d bytes, expected at least %d",
len(v), 32+32+1+2+1+1+64,
)
return
}
ev = new(event.E)
if err = ev.UnmarshalBinary(bytes.NewBuffer(v)); err != nil {
// Add more context to EOF errors for debugging
if err.Error() == "EOF" {
err = fmt.Errorf(
"EOF while unmarshaling event (serial=%v, data_len=%d): %w",
ser, len(v), err,
)
}
return
}
return
},
); err != nil {
return
}
return
}