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|
package ingest
import (
"bytes"
"encoding/binary"
"fmt"
"hash"
"io"
"slices"
"codeberg.org/lindenii/furgit/internal/intconv"
)
const (
idxMagicV2 = 0xff744f63
idxVersionV2 = 2
)
// writeIdx writes idx v2 for resolved records.
func writeIdx(state *ingestState) error {
order := buildIdxOrder(state)
hashImpl, err := state.algo.New()
if err != nil {
return err
}
write := func(src []byte) error {
_, err := state.idxFile.Write(src)
if err != nil {
return err
}
_, err = hashImpl.Write(src)
if err != nil {
return err
}
return nil
}
var scratch [8]byte
binary.BigEndian.PutUint32(scratch[:4], idxMagicV2)
binary.BigEndian.PutUint32(scratch[4:8], idxVersionV2)
err = write(scratch[:8])
if err != nil {
return err
}
var fanout [256]uint32
for _, recordIdx := range order {
idRaw := state.records[recordIdx].objectID.Bytes()
fanout[idRaw[0]]++
}
var cumulative uint32
for i := range fanout {
cumulative += fanout[i]
binary.BigEndian.PutUint32(scratch[:4], cumulative)
err := write(scratch[:4])
if err != nil {
return err
}
}
for _, recordIdx := range order {
idRaw := state.records[recordIdx].objectID.Bytes()
err := write(idRaw)
if err != nil {
return err
}
}
for _, recordIdx := range order {
binary.BigEndian.PutUint32(scratch[:4], state.records[recordIdx].crc32)
err := write(scratch[:4])
if err != nil {
return err
}
}
largeOffsets := make([]uint64, 0)
for _, recordIdx := range order {
offset := state.records[recordIdx].offset
if offset >= 0x80000000 {
largeOffsetIdx, err := intconv.IntToUint32(len(largeOffsets))
if err != nil {
return err
}
word := 0x80000000 | largeOffsetIdx
largeOffsets = append(largeOffsets, offset)
binary.BigEndian.PutUint32(scratch[:4], word)
} else {
binary.BigEndian.PutUint32(scratch[:4], uint32(offset))
}
err := write(scratch[:4])
if err != nil {
return err
}
}
for _, off := range largeOffsets {
binary.BigEndian.PutUint64(scratch[:8], off)
err := write(scratch[:8])
if err != nil {
return err
}
}
err = write(state.packHash.Bytes())
if err != nil {
return err
}
idxHash := hashImpl.Sum(nil)
_, err = state.idxFile.Write(idxHash)
if err != nil {
return err
}
return state.idxFile.Sync()
}
// buildIdxOrder returns record indexes sorted by ObjectID.
func buildIdxOrder(state *ingestState) []int {
out := make([]int, 0, len(state.records))
for idx := range state.records {
out = append(out, idx)
}
slices.SortFunc(out, func(a, b int) int {
return bytes.Compare(state.records[a].objectID.Bytes(), state.records[b].objectID.Bytes())
})
return out
}
// verifyResolvedRecords checks that all records are fully resolved before index writing.
func verifyResolvedRecords(state *ingestState) error {
for idx, record := range state.records {
if !record.resolved {
return fmt.Errorf("format/pack/ingest: unresolved record %d at offset %d", idx, record.offset)
}
}
return nil
}
// writeAndHash writes src to dst and updates hash.
func writeAndHash(dst io.Writer, hashImpl hash.Hash, src []byte) error {
_, err := dst.Write(src)
if err != nil {
return err
}
_, err = hashImpl.Write(src)
if err != nil {
return err
}
return nil
}
|
