mirror of https://github.com/dsoprea/go-exif.git
tags.go: Bugfix for bad FindFirst() error handling and not returning if not found
- utility.go: Add GetExifData() to return flat tags and extra data and to allow guessing of tags for misplaced IFDs. - exif-read-tool/main.go: Implement tag guessingdustin/master
Dustin Oprea
parent
df74da8384
commit
b4c2ca5765
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@ -130,13 +130,21 @@ var (
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typeNamesR = map[string]TagTypePrimitive{}
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)
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// Rational describes an unsigned rational value.
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type Rational struct {
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Numerator uint32
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// Numerator is the numerator of the rational value.
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Numerator uint32
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// Denominator is the numerator of the rational value.
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Denominator uint32
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}
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// SignedRational describes a signed rational value.
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type SignedRational struct {
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Numerator int32
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// Numerator is the numerator of the rational value.
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Numerator int32
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// Denominator is the numerator of the rational value.
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Denominator int32
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}
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@ -425,6 +433,18 @@ func GetTypeByName(typeName string) (tagType TagTypePrimitive, found bool) {
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return tagType, found
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}
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// BasicTag describes a single tag for any purpose.
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type BasicTag struct {
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// FqIfdPath is the fully-qualified IFD-path.
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FqIfdPath string
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// IfdPath is the unindexed IFD-path.
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IfdPath string
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// TagId is the tag-ID.
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TagId uint16
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}
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func init() {
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for typeId, typeName := range TypeNames {
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typeNamesR[typeName] = typeId
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@ -105,7 +105,7 @@ func main() {
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// Run the parse.
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entries, err := exif.GetFlatExifData(rawExif)
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entries, _, err := exif.GetExifData(rawExif, true)
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log.PanicIf(err)
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// Write the thumbnail is requested and present.
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12
v2/tags.go
12
v2/tags.go
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@ -272,7 +272,7 @@ var (
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// Things *can* end badly here, in that the same tag-ID in different IFDs might
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// describe different data and different ata-types, and our decode might then
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// produce binary and non-printable data.
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func (ti *TagIndex) FindFirst(id uint16, ifdIdentities []*exifcommon.IfdIdentity) (it *IndexedTag, err error) {
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func (ti *TagIndex) FindFirst(id uint16, typeId exifcommon.TagTypePrimitive, ifdIdentities []*exifcommon.IfdIdentity) (it *IndexedTag, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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@ -293,7 +293,15 @@ func (ti *TagIndex) FindFirst(id uint16, ifdIdentities []*exifcommon.IfdIdentity
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log.Panic(err)
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}
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return it, nil
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// Even though the tag might be mislocated, the type should still be the
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// same. Check this so we don't accidentally end-up on a complete
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// irrelevant tag with a totally different data type. This attempts to
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// mitigate producing garbage.
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for _, supportedType := range it.SupportedTypes {
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if supportedType == typeId {
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return it, nil
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}
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}
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}
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return nil, ErrTagNotFound
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@ -272,7 +272,7 @@ func TestTagIndex_FindFirst_HitOnFirst(t *testing.T) {
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ti := NewTagIndex()
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// ExifVersion
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it, err := ti.FindFirst(0x9000, searchOrder)
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it, err := ti.FindFirst(0x9000, exifcommon.TypeUndefined, searchOrder)
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log.PanicIf(err)
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if it.Is("IFD/Exif", 0x9000) != true {
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@ -290,7 +290,7 @@ func TestTagIndex_FindFirst_HitOnSecond(t *testing.T) {
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ti := NewTagIndex()
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// ProcessingSoftware
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it, err := ti.FindFirst(0x000b, searchOrder)
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it, err := ti.FindFirst(0x000b, exifcommon.TypeAscii, searchOrder)
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log.PanicIf(err)
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if it.Is("IFD", 0x000b) != true {
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@ -307,7 +307,7 @@ func TestTagIndex_FindFirst_DefaultOrder_Miss(t *testing.T) {
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ti := NewTagIndex()
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_, err := ti.FindFirst(0x1234, searchOrder)
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_, err := ti.FindFirst(0x1234, exifcommon.TypeRational, searchOrder)
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if err == nil {
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t.Fatalf("Expected error for invalid tag.")
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} else if err != ErrTagNotFound {
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@ -325,7 +325,7 @@ func TestTagIndex_FindFirst_ReverseDefaultOrder_HitOnSecond(t *testing.T) {
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ti := NewTagIndex()
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// ExifVersion
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it, err := ti.FindFirst(0x9000, reverseSearchOrder)
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it, err := ti.FindFirst(0x9000, exifcommon.TypeUndefined, reverseSearchOrder)
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log.PanicIf(err)
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if it.Is("IFD/Exif", 0x9000) != true {
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@ -343,7 +343,7 @@ func TestTagIndex_FindFirst_ReverseDefaultOrder_HitOnFirst(t *testing.T) {
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ti := NewTagIndex()
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// ProcessingSoftware
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it, err := ti.FindFirst(0x000b, reverseSearchOrder)
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it, err := ti.FindFirst(0x000b, exifcommon.TypeAscii, reverseSearchOrder)
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log.PanicIf(err)
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if it.Is("IFD", 0x000b) != true {
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@ -360,7 +360,7 @@ func TestTagIndex_FindFirst_ReverseDefaultOrder_Miss(t *testing.T) {
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ti := NewTagIndex()
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_, err := ti.FindFirst(0x1234, reverseSearchOrder)
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_, err := ti.FindFirst(0x1234, exifcommon.TypeRational, reverseSearchOrder)
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if err == nil {
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t.Fatalf("Expected error for invalid tag.")
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} else if err != ErrTagNotFound {
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105
v2/utility.go
105
v2/utility.go
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@ -116,10 +116,20 @@ type ExifTag struct {
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// String returns a string representation.
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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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return fmt.Sprintf(
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"ExifTag<"+
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"IFD-PATH=[%s] "+
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"TAG-ID=(0x%02x) "+
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"TAG-NAME=[%s] "+
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"TAG-TYPE=[%s] "+
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"VALUE=[%v] "+
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"VALUE-BYTES=(%d) "+
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"CHILD-IFD-PATH=[%s]",
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et.IfdPath, et.TagId, et.TagName, et.TagTypeName, et.FormattedFirst,
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len(et.ValueBytes), et.ChildIfdPath)
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}
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// RELEASE(dustin): In the next release, make this return a list of skipped tags, too.
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// RELEASE(dustin): In the next release, dump GetFlatExifData().
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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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@ -129,6 +139,33 @@ func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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}
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}()
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exifTags, _, err = GetExifData(exifData, false)
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log.PanicIf(err)
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return exifTags, nil
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}
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// MiscellaneousExifData is reports additional data collected during the parse.
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type MiscellaneousExifData struct {
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// UnknownTags contains all tags that were invalid for their containing
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// IFDs. The values represent alternative IFDs that were correctly matched
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// to those tags and used instead.
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UnknownTags map[exifcommon.BasicTag]exifcommon.BasicTag
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}
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// GetExifData returns a simple, flat representation of all tags along with
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// miscellaneous metadata..
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//
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// `doFindAlternativeIfds` indicates that we can attempt to find unknown tags in
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// other IFDs. This can help with malformed EXIF data, where tags might be in
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// IFDs other than specified by the EXIF specification.
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func GetExifData(exifData []byte, doFindAlternativeIfds bool) (exifTags []ExifTag, med MiscellaneousExifData, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(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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@ -139,6 +176,8 @@ func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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exifTags = make([]ExifTag, 0)
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med.UnknownTags = make(map[exifcommon.BasicTag]exifcommon.BasicTag)
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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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ii := ite.ifdIdentity
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@ -151,20 +190,56 @@ func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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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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it, err := ti.FindFirst(ite.tagId, nil)
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if err == nil {
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utilityLogger.Warningf(nil, "(cont'd) Tag [%s] with the same ID has been found in IFD [%s] and may be related. The tag you were looking for might have been written to the wrong IFD by a buggy implementation.", it.Name, it.IfdPath)
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originalBt := exifcommon.BasicTag{
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FqIfdPath: ii.String(),
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IfdPath: ii.UnindexedString(),
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TagId: ite.tagId,
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}
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return nil
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med.UnknownTags[originalBt] = exifcommon.BasicTag{}
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var err2 error
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it, err2 = ti.FindFirst(ite.tagId, ite.tagType, nil)
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if err2 == nil {
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utilityLogger.Warningf(nil,
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"Tag with ID (0x%04x) is not valid for IFD [%s], but it "+
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"*is* valid as tag [%s] under IFD [%s] and has the same "+
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"type [%s]. This EXIF blob was probably written by a buggy "+
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"implementation.",
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ite.tagId, ii.UnindexedString(), it.Name, it.IfdPath,
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ite.tagType)
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if doFindAlternativeIfds == false {
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utilityLogger.Warningf(nil,
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"We were told to not acknolwedge the alternative IFD "+
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"for the misplaced tag. Skipping.")
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return nil
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}
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med.UnknownTags[originalBt] = exifcommon.BasicTag{
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IfdPath: it.IfdPath,
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TagId: ite.tagId,
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}
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} else if err2 == ErrTagNotFound {
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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,
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"Tag with ID (0x%04x) in IFD [%s] is not recognized and "+
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"will be ignored.", tagId, fqIfdPath)
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return nil
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} else {
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log.Panic(err2)
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}
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// If we get here, we found the tag in a different place than
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// prescribed in the standard.
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}
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tagName := it.Name
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@ -217,7 +292,7 @@ func GetFlatExifData(exifData []byte) (exifTags []ExifTag, err error) {
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err = ie.Scan(exifcommon.IfdStandardIfdIdentity, eh.FirstIfdOffset, visitor)
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log.PanicIf(err)
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return exifTags, nil
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return exifTags, med, nil
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}
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func GpsDegreesEquals(gi1, gi2 GpsDegrees) bool {
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