// dbFetchTxIndexEntry uses an existing database transaction to fetch the block
// region for the provided transaction hash from the transaction index. When
// there is no entry for the provided hash, nil will be returned for the both
// the region and the error.
func dbFetchTxIndexEntry(dbTx database.Tx, txHash chainhash.Hash) (*database.BlockRegion, error) {
// Load the record from the database and return now if it doesn't exist.
txIndex := dbTx.Metadata().Bucket(txIndexKey)
serializedData := txIndex.Get(txHash[:])
if len(serializedData) == 0 {
return nil, nil
}
// Ensure the serialized data has enough bytes to properly deserialize.
if len(serializedData) < 12 {
return nil, database.Error{
ErrorCode: database.ErrCorruption,
Description: fmt.Sprintf("corrupt transaction index "+
"entry for %s", txHash),
}
}
// Load the block hash associated with the block ID.
hash, err := dbFetchBlockHashBySerializedID(dbTx, serializedData[0:4])
if err != nil {
return nil, database.Error{
ErrorCode: database.ErrCorruption,
Description: fmt.Sprintf("corrupt transaction index "+
"entry for %s: %v", txHash, err),
}
}
// Deserialize the final entry.
region := database.BlockRegion{Hash: &chainhash.Hash{}}
copy(region.Hash[:], hash[:])
region.Offset = byteOrder.Uint32(serializedData[4:8])
region.Len = byteOrder.Uint32(serializedData[8:12])
return ®ion, nil
}
// deserializeAddrIndexEntry decodes the passed serialized byte slice into the
// provided region struct according to the format described in detail above and
// uses the passed block hash fetching function in order to conver the block ID
// to the associated block hash.
func deserializeAddrIndexEntry(serialized []byte, region *database.BlockRegion, fetchBlockHash fetchBlockHashFunc) error {
// Ensure there are enough bytes to decode.
if len(serialized) < txEntrySize {
return errDeserialize("unexpected end of data")
}
hash, err := fetchBlockHash(serialized[0:4])
if err != nil {
return err
}
region.Hash = &hash
region.Offset = byteOrder.Uint32(serialized[4:8])
region.Len = byteOrder.Uint32(serialized[8:12])
return nil
}