// readPrefixOrFile executes a given func with a reader on the passed prefix and
// falls back to passing a reader on the whole file if the func returns an error.
func readPrefixOrFile(prefix []byte, fetcher blob.Fetcher, b *schema.Blob, fn func(filePrefixReader) error) (err error) {
pr := bytes.NewReader(prefix)
err = fn(pr)
if err == io.EOF || err == io.ErrUnexpectedEOF {
var fr *schema.FileReader
fr, err = b.NewFileReader(fetcher)
if err == nil {
err = fn(fr)
fr.Close()
}
}
return err
}
// b: the parsed file schema blob
// mm: keys to populate
func (ix *Index) populateFile(fetcher blob.Fetcher, b *schema.Blob, mm *mutationMap) (err error) {
var times []time.Time // all creation or mod times seen; may be zero
times = append(times, b.ModTime())
blobRef := b.BlobRef()
fr, err := b.NewFileReader(fetcher)
if err != nil {
return err
}
defer fr.Close()
mime, reader := magic.MIMETypeFromReader(fr)
sha1 := sha1.New()
var copyDest io.Writer = sha1
var imageBuf *keepFirstN // or nil
if strings.HasPrefix(mime, "image/") {
imageBuf = &keepFirstN{N: 512 << 10}
copyDest = io.MultiWriter(copyDest, imageBuf)
}
size, err := io.Copy(copyDest, reader)
if err != nil {
return err
}
wholeRef := blob.RefFromHash(sha1)
if imageBuf != nil {
conf, err := images.DecodeConfig(bytes.NewReader(imageBuf.Bytes))
// If our optimistic 512KB in-memory prefix from above was too short to get the dimensions, pass the whole thing instead and try again.
if err == io.ErrUnexpectedEOF {
var fr *schema.FileReader
fr, err = b.NewFileReader(fetcher)
if err == nil {
conf, err = images.DecodeConfig(fr)
fr.Close()
}
}
if err == nil {
mm.Set(keyImageSize.Key(blobRef), keyImageSize.Val(fmt.Sprint(conf.Width), fmt.Sprint(conf.Height)))
}
if ft, err := schema.FileTime(bytes.NewReader(imageBuf.Bytes)); err == nil {
log.Printf("filename %q exif = %v, %v", b.FileName(), ft, err)
times = append(times, ft)
} else {
log.Printf("filename %q exif = %v, %v", b.FileName(), ft, err)
}
// TODO(mpl): find (generate?) more broken EXIF images to experiment with.
err = indexEXIF(wholeRef, bytes.NewReader(imageBuf.Bytes), mm)
if err == io.EOF {
var fr *schema.FileReader
fr, err = b.NewFileReader(fetcher)
if err == nil {
err = indexEXIF(wholeRef, fr, mm)
fr.Close()
}
}
if err != nil {
log.Printf("error parsing EXIF: %v", err)
}
}
var sortTimes []time.Time
for _, t := range times {
if !t.IsZero() {
sortTimes = append(sortTimes, t)
}
}
sort.Sort(types.ByTime(sortTimes))
var time3339s string
switch {
case len(sortTimes) == 1:
time3339s = types.Time3339(sortTimes[0]).String()
case len(sortTimes) >= 2:
oldest, newest := sortTimes[0], sortTimes[len(sortTimes)-1]
time3339s = types.Time3339(oldest).String() + "," + types.Time3339(newest).String()
}
mm.Set(keyWholeToFileRef.Key(wholeRef, blobRef), "1")
mm.Set(keyFileInfo.Key(blobRef), keyFileInfo.Val(size, b.FileName(), mime, wholeRef))
mm.Set(keyFileTimes.Key(blobRef), keyFileTimes.Val(time3339s))
if strings.HasPrefix(mime, "audio/") {
indexMusic(io.NewSectionReader(fr, 0, fr.Size()), wholeRef, mm)
}
return nil
}