mfer/mfer/serialize.go

101 lines
1.9 KiB
Go

package mfer
import (
"bytes"
"compress/gzip"
"crypto/sha256"
"errors"
"time"
"google.golang.org/protobuf/proto"
)
//go:generate protoc --go_out=. --go_opt=paths=source_relative mf.proto
// rot13("MANIFEST")
const MAGIC string = "ZNAVSRFG"
func newTimestampFromTime(t time.Time) *Timestamp {
out := &Timestamp{
Seconds: t.Unix(),
Nanos: int32(t.UnixNano() - (t.Unix() * 1000000000)),
}
return out
}
func (m *manifest) generate() error {
if m.pbInner == nil {
e := m.generateInner()
if e != nil {
return e
}
}
if m.pbOuter == nil {
e := m.generateOuter()
if e != nil {
return e
}
}
dat, err := proto.MarshalOptions{Deterministic: true}.Marshal(m.pbOuter)
if err != nil {
return err
}
m.output = bytes.NewBuffer([]byte(MAGIC))
_, err = m.output.Write(dat)
if err != nil {
return err
}
return nil
}
func (m *manifest) generateOuter() error {
if m.pbInner == nil {
return errors.New("internal error")
}
innerData, err := proto.MarshalOptions{Deterministic: true}.Marshal(m.pbInner)
if err != nil {
return err
}
h := sha256.New()
h.Write(innerData)
idc := new(bytes.Buffer)
gzw, err := gzip.NewWriterLevel(idc, gzip.BestCompression)
if err != nil {
return err
}
_, err = gzw.Write(innerData)
if err != nil {
return err
}
gzw.Close()
o := &MFFileOuter{
InnerMessage: idc.Bytes(),
Size: int64(len(innerData)),
Sha256: h.Sum(nil),
Version: MFFileOuter_VERSION_ONE,
CompressionType: MFFileOuter_COMPRESSION_GZIP,
}
m.pbOuter = o
return nil
}
func (m *manifest) generateInner() error {
m.pbInner = &MFFile{
Version: MFFile_VERSION_ONE,
CreatedAt: newTimestampFromTime(time.Now()),
Files: []*MFFilePath{},
}
for _, f := range m.files {
nf := &MFFilePath{
Path: f.path,
// FIXME add more stuff
}
m.pbInner.Files = append(m.pbInner.Files, nf)
}
return nil
}