gotosocial/vendor/github.com/dsoprea/go-jpeg-image-structure/segment.go
Tobi Smethurst 98263a7de6
Grand test fixup (#138)
* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig
2021-08-12 21:03:24 +02:00

349 lines
7.3 KiB
Go

package jpegstructure
import (
"bytes"
"errors"
"fmt"
"crypto/sha1"
"encoding/hex"
"github.com/dsoprea/go-exif/v2"
"github.com/dsoprea/go-iptc"
"github.com/dsoprea/go-logging"
"github.com/dsoprea/go-photoshop-info-format"
"github.com/dsoprea/go-utility/image"
)
const (
pirIptcImageResourceId = uint16(0x0404)
)
var (
// exifPrefix is the prefix found at the top of an EXIF slice. This is JPEG-
// specific.
exifPrefix = []byte{'E', 'x', 'i', 'f', 0, 0}
xmpPrefix = []byte("http://ns.adobe.com/xap/1.0/\000")
ps30Prefix = []byte("Photoshop 3.0\000")
)
var (
// ErrNoXmp is returned if XMP data was requested but not found.
ErrNoXmp = errors.New("no XMP data")
// ErrNoIptc is returned if IPTC data was requested but not found.
ErrNoIptc = errors.New("no IPTC data")
// ErrNoPhotoshopData is returned if Photoshop info was requested but not
// found.
ErrNoPhotoshopData = errors.New("no photoshop data")
)
// SofSegment has info read from a SOF segment.
type SofSegment struct {
// BitsPerSample is the bits-per-sample.
BitsPerSample byte
// Width is the image width.
Width uint16
// Height is the image height.
Height uint16
// ComponentCount is the number of color components.
ComponentCount byte
}
// String returns a string representation of the SOF segment.
func (ss SofSegment) String() string {
// TODO(dustin): Add test
return fmt.Sprintf("SOF<BitsPerSample=(%d) Width=(%d) Height=(%d) ComponentCount=(%d)>", ss.BitsPerSample, ss.Width, ss.Height, ss.ComponentCount)
}
// SegmentVisitor describes a segment-visitor struct.
type SegmentVisitor interface {
// HandleSegment is triggered for each segment encountered as well as the
// scan-data.
HandleSegment(markerId byte, markerName string, counter int, lastIsScanData bool) error
}
// SofSegmentVisitor describes a visitor that is only called for each SOF
// segment.
type SofSegmentVisitor interface {
// HandleSof is called for each encountered SOF segment.
HandleSof(sof *SofSegment) error
}
// Segment describes a single segment.
type Segment struct {
MarkerId byte
MarkerName string
Offset int
Data []byte
photoshopInfo map[uint16]photoshopinfo.Photoshop30InfoRecord
iptcTags map[iptc.StreamTagKey][]iptc.TagData
}
// SetExif encodes and sets EXIF data into this segment.
func (s *Segment) SetExif(ib *exif.IfdBuilder) (err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
ibe := exif.NewIfdByteEncoder()
exifData, err := ibe.EncodeToExif(ib)
log.PanicIf(err)
l := len(exifPrefix)
s.Data = make([]byte, l+len(exifData))
copy(s.Data[0:], exifPrefix)
copy(s.Data[l:], exifData)
return nil
}
// Exif returns an `exif.Ifd` instance for the EXIF data we currently have.
func (s *Segment) Exif() (rootIfd *exif.Ifd, data []byte, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
l := len(exifPrefix)
rawExif := s.Data[l:]
jpegLogger.Debugf(nil, "Attempting to parse (%d) byte EXIF blob (Exif).", len(rawExif))
im := exif.NewIfdMappingWithStandard()
ti := exif.NewTagIndex()
_, index, err := exif.Collect(im, ti, rawExif)
log.PanicIf(err)
return index.RootIfd, rawExif, nil
}
// FlatExif parses the EXIF data and just returns a list of tags.
func (s *Segment) FlatExif() (exifTags []exif.ExifTag, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
// TODO(dustin): Add test
l := len(exifPrefix)
rawExif := s.Data[l:]
jpegLogger.Debugf(nil, "Attempting to parse (%d) byte EXIF blob (FlatExif).", len(rawExif))
exifTags, err = exif.GetFlatExifData(rawExif)
log.PanicIf(err)
return exifTags, nil
}
// EmbeddedString returns a string of properties that can be embedded into an
// longer string of properties.
func (s *Segment) EmbeddedString() string {
h := sha1.New()
h.Write(s.Data)
// TODO(dustin): Add test
digestString := hex.EncodeToString(h.Sum(nil))
return fmt.Sprintf("OFFSET=(0x%08x %10d) ID=(0x%02x) NAME=[%-5s] SIZE=(%10d) SHA1=[%s]", s.Offset, s.Offset, s.MarkerId, markerNames[s.MarkerId], len(s.Data), digestString)
}
// String returns a descriptive string.
func (s *Segment) String() string {
// TODO(dustin): Add test
return fmt.Sprintf("Segment<%s>", s.EmbeddedString())
}
// IsExif returns true if EXIF data.
func (s *Segment) IsExif() bool {
if s.MarkerId != MARKER_APP1 {
return false
}
// TODO(dustin): Add test
l := len(exifPrefix)
if len(s.Data) < l {
return false
}
if bytes.Equal(s.Data[:l], exifPrefix) == false {
return false
}
return true
}
// IsXmp returns true if XMP data.
func (s *Segment) IsXmp() bool {
if s.MarkerId != MARKER_APP1 {
return false
}
// TODO(dustin): Add test
l := len(xmpPrefix)
if len(s.Data) < l {
return false
}
if bytes.Equal(s.Data[:l], xmpPrefix) == false {
return false
}
return true
}
// FormattedXmp returns a formatted XML string. This only makes sense for a
// segment comprised of XML data (like XMP).
func (s *Segment) FormattedXmp() (formatted string, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
// TODO(dustin): Add test
if s.IsXmp() != true {
log.Panicf("not an XMP segment")
}
l := len(xmpPrefix)
raw := string(s.Data[l:])
formatted, err = FormatXml(raw)
log.PanicIf(err)
return formatted, nil
}
func (s *Segment) parsePhotoshopInfo() (photoshopInfo map[uint16]photoshopinfo.Photoshop30InfoRecord, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
if s.photoshopInfo != nil {
return s.photoshopInfo, nil
}
if s.MarkerId != MARKER_APP13 {
return nil, ErrNoPhotoshopData
}
l := len(ps30Prefix)
if len(s.Data) < l {
return nil, ErrNoPhotoshopData
}
if bytes.Equal(s.Data[:l], ps30Prefix) == false {
return nil, ErrNoPhotoshopData
}
data := s.Data[l:]
b := bytes.NewBuffer(data)
// Parse it.
pirIndex, err := photoshopinfo.ReadPhotoshop30Info(b)
log.PanicIf(err)
s.photoshopInfo = pirIndex
return s.photoshopInfo, nil
}
// IsIptc returns true if XMP data.
func (s *Segment) IsIptc() bool {
// TODO(dustin): Add test
// There's a cost to determining if there's IPTC data, so we won't do it
// more than once.
if s.iptcTags != nil {
return true
}
photoshopInfo, err := s.parsePhotoshopInfo()
if err != nil {
if err == ErrNoPhotoshopData {
return false
}
log.Panic(err)
}
// Bail if the Photoshop info doesn't have IPTC data.
_, found := photoshopInfo[pirIptcImageResourceId]
if found == false {
return false
}
return true
}
// Iptc parses Photoshop info (if present) and then parses the IPTC info inside
// it (if present).
func (s *Segment) Iptc() (tags map[iptc.StreamTagKey][]iptc.TagData, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
// Cache the parse.
if s.iptcTags != nil {
return s.iptcTags, nil
}
photoshopInfo, err := s.parsePhotoshopInfo()
log.PanicIf(err)
iptcPir, found := photoshopInfo[pirIptcImageResourceId]
if found == false {
return nil, ErrNoIptc
}
b := bytes.NewBuffer(iptcPir.Data)
tags, err = iptc.ParseStream(b)
log.PanicIf(err)
s.iptcTags = tags
return tags, nil
}
var (
// Enforce interface conformance.
_ riimage.MediaContext = new(Segment)
)