mirror of https://github.com/dsoprea/go-exif.git
utility.go: Reduce duplication in `GetFlatExifData()` and just use `Scan()`
Dustin Oprea
parent
0f18278742
commit
753e5191d6
168
v2/utility.go
168
v2/utility.go
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@ -77,21 +77,40 @@ func ExifFullTimestampString(t time.Time) (fullTimestampPhrase string) {
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// ExifTag is one simple representation of a tag in a flat list of all of them.
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type ExifTag struct {
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// IfdPath is the fully-qualified IFD path (even though it is not named as
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// such).
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IfdPath string `json:"ifd_path"`
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TagId uint16 `json:"id"`
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// TagId is the tag-ID.
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TagId uint16 `json:"id"`
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// TagName is the tag-name. This is never empty.
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TagName string `json:"name"`
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// UnitCount is the recorded number of units constution of the value.
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UnitCount uint32 `json:"unit_count"`
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TagTypeId exifcommon.TagTypePrimitive `json:"type_id"`
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TagTypeName string `json:"type_name"`
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Value interface{} `json:"value"`
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ValueBytes []byte `json:"value_bytes"`
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// TagTypeId is the type-ID.
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TagTypeId exifcommon.TagTypePrimitive `json:"type_id"`
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// TagTypeName is the type name.
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TagTypeName string `json:"type_name"`
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// Value is the decoded value.
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Value interface{} `json:"value"`
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// ValueBytes is the raw, encoded value.
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ValueBytes []byte `json:"value_bytes"`
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// Formatted is the human representation of the first value (tag values are
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// always an array).
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FormattedFirst string `json:"formatted_first"`
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Formatted string `json:"formatted"`
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// Formatted is the human representation of the complete value.
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Formatted string `json:"formatted"`
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// ChildIfdPath is the name of the child IFD this tag represents (if it
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// represents any). Otherwise, this is empty.
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ChildIfdPath string `json:"child_ifd_path"`
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}
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@ -100,6 +119,8 @@ func (et ExifTag) String() string {
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return fmt.Sprintf("ExifTag<IFD-PATH=[%s] TAG-ID=(0x%02x) TAG-NAME=[%s] TAG-TYPE=[%s] VALUE=[%v] VALUE-BYTES=(%d) CHILD-IFD-PATH=[%s]", et.IfdPath, et.TagId, et.TagName, et.TagTypeName, et.FormattedFirst, len(et.ValueBytes), et.ChildIfdPath)
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}
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// TODO(dustin): In the next release, make this return a list of skipped tags, too.
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// GetFlatExifData returns a simple, flat representation of all tags.
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func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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defer func() {
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@ -108,95 +129,92 @@ func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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}
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}()
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eh, err := ParseExifHeader(exifData)
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log.PanicIf(err)
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im := NewIfdMappingWithStandard()
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ti := NewTagIndex()
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_, index, err := Collect(im, ti, exifData)
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log.PanicIf(err)
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q := []*Ifd{index.RootIfd}
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ie := NewIfdEnumerate(im, ti, exifData, eh.ByteOrder)
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exifTags = make([]ExifTag, 0)
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for len(q) > 0 {
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var ifd *Ifd
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ifd, q = q[0], q[1:]
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visitor := func(fqIfdPath string, ifdIndex int, ite *IfdTagEntry) (err error) {
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tagId := ite.TagId()
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for _, ite := range ifd.Entries {
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tagId := ite.TagId()
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tagType := ite.TagType()
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tagName := ""
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it, err := ti.Get(ifd.IfdPath, ite.tagId)
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if err != nil {
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if log.Is(err, ErrTagNotFound) != true {
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log.Panic(err)
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}
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// This is an unknown tag.
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// This is supposed to be a convenience function and if we were
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// to keep the name empty or set it to some placeholder, it
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// might be mismanaged by the package that is calling us. If
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// they want to specifically manage these types of tags, they
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// can use more advanced functionality to specifically -handle
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// unknown tags.
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utilityLogger.Warningf(nil, "Tag with ID (0x%04x) in IFD [%s] is not recognized and will be ignored.", tagId, ifd.FqIfdPath)
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continue
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} else {
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tagName = it.Name
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}
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valueBytes, err := ite.GetRawBytes()
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if err != nil {
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if err == exifundefined.ErrUnparseableValue {
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continue
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}
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// TODO(dustin): This is inefficient. Our IFD paths should have their own type where we can render whatever path we need.
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ifdPath, err := im.StripPathPhraseIndices(fqIfdPath)
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log.PanicIf(err)
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it, err := ti.Get(ifdPath, ite.tagId)
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if err != nil {
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if log.Is(err, ErrTagNotFound) != true {
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log.Panic(err)
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}
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value, err := ite.Value()
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if err != nil {
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if err == exifcommon.ErrUnhandledUndefinedTypedTag {
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value = exifundefined.UnparseableUnknownTagValuePlaceholder
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} else {
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log.Panic(err)
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}
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// This is an unknown tag.
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// This is supposed to be a convenience function and if we were
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// to keep the name empty or set it to some placeholder, it
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// might be mismanaged by the package that is calling us. If
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// they want to specifically manage these types of tags, they
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// can use more advanced functionality to specifically -handle
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// unknown tags.
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utilityLogger.Warningf(nil, "Tag with ID (0x%04x) in IFD [%s] is not recognized and will be ignored.", tagId, fqIfdPath)
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return nil
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}
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tagName := it.Name
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// This encodes down to base64. Since this an example tool and we do not
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// expect to ever decode the output, we are not worried about
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// specifically base64-encoding it in order to have a measure of
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// control.
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valueBytes, err := ite.GetRawBytes()
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if err != nil {
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if err == exifundefined.ErrUnparseableValue {
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return nil
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}
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et := ExifTag{
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IfdPath: ifd.FqIfdPath,
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TagId: tagId,
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TagName: tagName,
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UnitCount: ite.UnitCount(),
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TagTypeId: tagType,
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TagTypeName: tagType.String(),
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Value: value,
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ValueBytes: valueBytes,
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ChildIfdPath: ite.ChildIfdPath(),
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log.Panic(err)
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}
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value, err := ite.Value()
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if err != nil {
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if err == exifcommon.ErrUnhandledUndefinedTypedTag {
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value = exifundefined.UnparseableUnknownTagValuePlaceholder
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} else {
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log.Panic(err)
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}
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et.Formatted, err = ite.Format()
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log.PanicIf(err)
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et.FormattedFirst, err = ite.FormatFirst()
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log.PanicIf(err)
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exifTags = append(exifTags, et)
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}
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for _, childIfd := range ifd.Children {
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q = append(q, childIfd)
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et := ExifTag{
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IfdPath: fqIfdPath,
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TagId: tagId,
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TagName: tagName,
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UnitCount: ite.UnitCount(),
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TagTypeId: ite.TagType(),
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TagTypeName: ite.TagType().String(),
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Value: value,
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ValueBytes: valueBytes,
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ChildIfdPath: ite.ChildIfdPath(),
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}
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if ifd.NextIfd != nil {
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q = append(q, ifd.NextIfd)
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}
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et.Formatted, err = ite.Format()
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log.PanicIf(err)
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et.FormattedFirst, err = ite.FormatFirst()
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log.PanicIf(err)
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exifTags = append(exifTags, et)
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return nil
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}
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err = ie.Scan(exifcommon.IfdStandard, eh.FirstIfdOffset, visitor)
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log.PanicIf(err)
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return exifTags, nil
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}
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