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|
package ingest
import (
"encoding/binary"
"slices"
"codeberg.org/lindenii/furgit/objectid"
)
const (
revMagic = 0x52494458
revVersion = 1
)
// writeRev writes rev index for resolved records.
func writeRev(state *ingestState) error {
if !state.writeRev {
return nil
}
idxOrder := buildIdxOrder(state)
recordToIdxPos := make([]int, len(state.records))
for pos, recordIdx := range idxOrder {
recordToIdxPos[recordIdx] = pos
}
packOrder := buildPackOrder(state)
hashImpl, err := state.algo.New()
if err != nil {
return err
}
var scratch [8]byte
binary.BigEndian.PutUint32(scratch[:4], revMagic)
if err := writeAndHash(state.revFile, hashImpl, scratch[:4]); err != nil {
return err
}
binary.BigEndian.PutUint32(scratch[:4], revVersion)
if err := writeAndHash(state.revFile, hashImpl, scratch[:4]); err != nil {
return err
}
binary.BigEndian.PutUint32(scratch[:4], hashID(state.algo))
if err := writeAndHash(state.revFile, hashImpl, scratch[:4]); err != nil {
return err
}
for _, recordIdx := range packOrder {
binary.BigEndian.PutUint32(scratch[:4], uint32(recordToIdxPos[recordIdx]))
if err := writeAndHash(state.revFile, hashImpl, scratch[:4]); err != nil {
return err
}
}
if err := writeAndHash(state.revFile, hashImpl, state.packHash.Bytes()); err != nil {
return err
}
revHash := hashImpl.Sum(nil)
if _, err := state.revFile.Write(revHash); err != nil {
return err
}
return state.revFile.Sync()
}
// buildPackOrder returns record indexes sorted by pack offset.
func buildPackOrder(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 {
offA := state.records[a].offset
offB := state.records[b].offset
switch {
case offA < offB:
return -1
case offA > offB:
return 1
default:
return 0
}
})
return out
}
// hashID converts object algorithm to pack hash-id encoding.
func hashID(algo objectid.Algorithm) uint32 {
switch algo {
case objectid.AlgorithmSHA1:
return 1
case objectid.AlgorithmSHA256:
return 2
default:
return 0
}
}
|
