mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 06:30:41 +01:00
1673 lines
44 KiB
Go
1673 lines
44 KiB
Go
package exif
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"strconv"
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"strings"
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"time"
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"encoding/binary"
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"github.com/dsoprea/go-logging"
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"github.com/dsoprea/go-exif/v3/common"
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"github.com/dsoprea/go-exif/v3/undefined"
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)
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var (
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ifdEnumerateLogger = log.NewLogger("exif.ifd_enumerate")
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)
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var (
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// ErrNoThumbnail means that no thumbnail was found.
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ErrNoThumbnail = errors.New("no thumbnail")
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// ErrNoGpsTags means that no GPS info was found.
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ErrNoGpsTags = errors.New("no gps tags")
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// ErrTagTypeNotValid means that the tag-type is not valid.
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ErrTagTypeNotValid = errors.New("tag type invalid")
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// ErrOffsetInvalid means that the file offset is not valid.
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ErrOffsetInvalid = errors.New("file offset invalid")
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)
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var (
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// ValidGpsVersions is the list of recognized EXIF GPS versions/signatures.
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ValidGpsVersions = [][4]byte{
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// 2.0.0.0 appears to have a very similar format to 2.2.0.0, so enabling
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// it under that assumption.
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//
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// IFD-PATH=[IFD] ID=(0x8825) NAME=[GPSTag] COUNT=(1) TYPE=[LONG] VALUE=[114]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0000) NAME=[GPSVersionID] COUNT=(4) TYPE=[BYTE] VALUE=[02 00 00 00]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0001) NAME=[GPSLatitudeRef] COUNT=(2) TYPE=[ASCII] VALUE=[S]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0002) NAME=[GPSLatitude] COUNT=(3) TYPE=[RATIONAL] VALUE=[38/1...]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0003) NAME=[GPSLongitudeRef] COUNT=(2) TYPE=[ASCII] VALUE=[E]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0004) NAME=[GPSLongitude] COUNT=(3) TYPE=[RATIONAL] VALUE=[144/1...]
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// IFD-PATH=[IFD/GPSInfo] ID=(0x0012) NAME=[GPSMapDatum] COUNT=(7) TYPE=[ASCII] VALUE=[WGS-84]
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//
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{2, 0, 0, 0},
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{2, 2, 0, 0},
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// Suddenly appeared at the default in 2.31: https://home.jeita.or.jp/tsc/std-pdf/CP-3451D.pdf
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//
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// Note that the presence of 2.3.0.0 doesn't seem to guarantee
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// coordinates. In some cases, we seen just the following:
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//
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// GPS Tag Version |2.3.0.0
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// GPS Receiver Status |V
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// Geodetic Survey Data|WGS-84
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// GPS Differential Cor|0
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//
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{2, 3, 0, 0},
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}
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)
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// byteParser knows how to decode an IFD and all of the tags it
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// describes.
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//
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// The IFDs and the actual values can float throughout the EXIF block, but the
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// IFD itself is just a minor header followed by a set of repeating,
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// statically-sized records. So, the tags (though notnecessarily their values)
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// are fairly simple to enumerate.
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type byteParser struct {
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byteOrder binary.ByteOrder
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rs io.ReadSeeker
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ifdOffset uint32
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currentOffset uint32
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}
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// newByteParser returns a new byteParser struct.
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//
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// initialOffset is for arithmetic-based tracking of where we should be at in
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// the stream.
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func newByteParser(rs io.ReadSeeker, byteOrder binary.ByteOrder, initialOffset uint32) (bp *byteParser, err error) {
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// TODO(dustin): Add test
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bp = &byteParser{
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rs: rs,
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byteOrder: byteOrder,
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currentOffset: initialOffset,
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}
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return bp, nil
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}
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// getUint16 reads a uint16 and advances both our current and our current
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// accumulator (which allows us to know how far to seek to the beginning of the
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// next IFD when it's time to jump).
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func (bp *byteParser) getUint16() (value uint16, raw []byte, 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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// TODO(dustin): Add test
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needBytes := 2
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raw = make([]byte, needBytes)
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_, err = io.ReadFull(bp.rs, raw)
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log.PanicIf(err)
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value = bp.byteOrder.Uint16(raw)
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bp.currentOffset += uint32(needBytes)
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return value, raw, nil
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}
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// getUint32 reads a uint32 and advances both our current and our current
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// accumulator (which allows us to know how far to seek to the beginning of the
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// next IFD when it's time to jump).
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func (bp *byteParser) getUint32() (value uint32, raw []byte, 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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// TODO(dustin): Add test
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needBytes := 4
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raw = make([]byte, needBytes)
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_, err = io.ReadFull(bp.rs, raw)
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log.PanicIf(err)
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value = bp.byteOrder.Uint32(raw)
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bp.currentOffset += uint32(needBytes)
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return value, raw, nil
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}
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// CurrentOffset returns the starting offset but the number of bytes that we
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// have parsed. This is arithmetic-based tracking, not a seek(0) operation.
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func (bp *byteParser) CurrentOffset() uint32 {
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return bp.currentOffset
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}
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// IfdEnumerate is the main enumeration type. It knows how to parse the IFD
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// containers in the EXIF blob.
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type IfdEnumerate struct {
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ebs ExifBlobSeeker
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byteOrder binary.ByteOrder
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tagIndex *TagIndex
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ifdMapping *exifcommon.IfdMapping
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furthestOffset uint32
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visitedIfdOffsets map[uint32]struct{}
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}
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// NewIfdEnumerate returns a new instance of IfdEnumerate.
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func NewIfdEnumerate(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, ebs ExifBlobSeeker, byteOrder binary.ByteOrder) *IfdEnumerate {
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return &IfdEnumerate{
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ebs: ebs,
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byteOrder: byteOrder,
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ifdMapping: ifdMapping,
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tagIndex: tagIndex,
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visitedIfdOffsets: make(map[uint32]struct{}),
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}
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}
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func (ie *IfdEnumerate) getByteParser(ifdOffset uint32) (bp *byteParser, 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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initialOffset := ExifAddressableAreaStart + ifdOffset
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rs, err := ie.ebs.GetReadSeeker(int64(initialOffset))
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log.PanicIf(err)
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bp, err =
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newByteParser(
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rs,
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ie.byteOrder,
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initialOffset)
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if err != nil {
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if err == ErrOffsetInvalid {
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return nil, err
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}
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log.Panic(err)
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}
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return bp, nil
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}
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func (ie *IfdEnumerate) parseTag(ii *exifcommon.IfdIdentity, tagPosition int, bp *byteParser) (ite *IfdTagEntry, 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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tagId, _, err := bp.getUint16()
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log.PanicIf(err)
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tagTypeRaw, _, err := bp.getUint16()
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log.PanicIf(err)
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tagType := exifcommon.TagTypePrimitive(tagTypeRaw)
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unitCount, _, err := bp.getUint32()
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log.PanicIf(err)
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valueOffset, rawValueOffset, err := bp.getUint32()
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log.PanicIf(err)
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// Check whether the embedded type indicator is valid.
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if tagType.IsValid() == false {
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// Technically, we have the type on-file in the tags-index, but
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// if the type stored alongside the data disagrees with it,
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// which it apparently does, all bets are off.
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ifdEnumerateLogger.Warningf(nil,
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"Tag (0x%04x) in IFD [%s] at position (%d) has invalid type (0x%04x) and will be skipped.",
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tagId, ii, tagPosition, int(tagType))
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ite = &IfdTagEntry{
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tagId: tagId,
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tagType: tagType,
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}
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return ite, ErrTagTypeNotValid
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}
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// Check whether the embedded type is listed among the supported types for
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// the registered tag. If not, skip processing the tag.
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it, err := ie.tagIndex.Get(ii, tagId)
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if err != nil {
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if log.Is(err, ErrTagNotFound) == true {
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ifdEnumerateLogger.Warningf(nil, "Tag (0x%04x) is not known and will be skipped.", tagId)
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ite = &IfdTagEntry{
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tagId: tagId,
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}
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return ite, ErrTagNotFound
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}
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log.Panic(err)
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}
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// If we're trying to be as forgiving as possible then use whatever type was
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// reported in the format. Otherwise, only accept a type that's expected for
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// this tag.
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if ie.tagIndex.UniversalSearch() == false && it.DoesSupportType(tagType) == false {
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// The type in the stream disagrees with the type that this tag is
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// expected to have. This can present issues with how we handle the
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// special-case tags (e.g. thumbnails, GPS, etc..) when those tags
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// suddenly have data that we no longer manipulate correctly/
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// accurately.
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ifdEnumerateLogger.Warningf(nil,
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"Tag (0x%04x) in IFD [%s] at position (%d) has unsupported type (0x%02x) and will be skipped.",
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tagId, ii, tagPosition, int(tagType))
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return nil, ErrTagTypeNotValid
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}
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// Construct tag struct.
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rs, err := ie.ebs.GetReadSeeker(0)
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log.PanicIf(err)
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ite = newIfdTagEntry(
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ii,
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tagId,
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tagPosition,
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tagType,
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unitCount,
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valueOffset,
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rawValueOffset,
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rs,
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ie.byteOrder)
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ifdPath := ii.UnindexedString()
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// If it's an IFD but not a standard one, it'll just be seen as a LONG
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// (the standard IFD tag type), later, unless we skip it because it's
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// [likely] not even in the standard list of known tags.
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mi, err := ie.ifdMapping.GetChild(ifdPath, tagId)
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if err == nil {
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currentIfdTag := ii.IfdTag()
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childIt := exifcommon.NewIfdTag(¤tIfdTag, tagId, mi.Name)
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iiChild := ii.NewChild(childIt, 0)
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ite.SetChildIfd(iiChild)
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// We also need to set `tag.ChildFqIfdPath` but can't do it here
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// because we don't have the IFD index.
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} else if log.Is(err, exifcommon.ErrChildIfdNotMapped) == false {
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log.Panic(err)
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}
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return ite, nil
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}
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// TagVisitorFn is called for each tag when enumerating through the EXIF.
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type TagVisitorFn func(ite *IfdTagEntry) (err error)
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// tagPostParse do some tag-level processing here following the parse of each.
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func (ie *IfdEnumerate) tagPostParse(ite *IfdTagEntry, 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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// TODO(dustin): Add test
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ii := ite.IfdIdentity()
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tagId := ite.TagId()
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tagType := ite.TagType()
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it, err := ie.tagIndex.Get(ii, tagId)
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if err == nil {
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ite.setTagName(it.Name)
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} else {
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if err != ErrTagNotFound {
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log.Panic(err)
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}
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// This is an unknown tag.
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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: tagId,
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}
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if med != nil {
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med.unknownTags[originalBt] = exifcommon.BasicTag{}
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}
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utilityLogger.Debugf(nil,
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"Tag (0x%04x) is not valid for IFD [%s]. Attempting secondary "+
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"lookup.", tagId, ii.String())
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// This will overwrite the existing `it` and `err`. Since `FindFirst()`
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// might generate different Errors than `Get()`, the log message above
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// is import to try and mitigate confusion in that case.
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it, err = ie.tagIndex.FindFirst(tagId, tagType, nil)
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if err != nil {
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if err != ErrTagNotFound {
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log.Panic(err)
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}
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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, ii.String())
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return ErrTagNotFound
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}
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ite.setTagName(it.Name)
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utilityLogger.Warningf(nil,
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"Tag with ID (0x%04x) is not valid for IFD [%s], but it *is* "+
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"valid as tag [%s] under IFD [%s] and has the same type "+
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"[%s], so we will use that. This EXIF blob was probably "+
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"written by a buggy implementation.",
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tagId, ii.UnindexedString(), it.Name, it.IfdPath,
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tagType)
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if med != nil {
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med.unknownTags[originalBt] = exifcommon.BasicTag{
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IfdPath: it.IfdPath,
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TagId: tagId,
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}
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}
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}
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// This is a known tag (from the standard, unless the user did
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// something different).
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// Skip any tags that have a type that doesn't match the type in the
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// index (which is loaded with the standard and accept tag
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// information unless configured otherwise).
|
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//
|
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// We've run into multiple instances of the same tag, where a) no
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// tag should ever be repeated, and b) all but one had an incorrect
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// type and caused parsing/conversion woes. So, this is a quick fix
|
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// for those scenarios.
|
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if ie.tagIndex.UniversalSearch() == false && it.DoesSupportType(tagType) == false {
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ifdEnumerateLogger.Warningf(nil,
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"Skipping tag [%s] (0x%04x) [%s] with an unexpected type: %v ∉ %v",
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ii.UnindexedString(), tagId, it.Name,
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tagType, it.SupportedTypes)
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return ErrTagNotFound
|
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}
|
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return nil
|
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}
|
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|
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// parseIfd decodes the IFD block that we're currently sitting on the first
|
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// byte of.
|
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func (ie *IfdEnumerate) parseIfd(ii *exifcommon.IfdIdentity, bp *byteParser, visitor TagVisitorFn, doDescend bool, med *MiscellaneousExifData) (nextIfdOffset uint32, entries []*IfdTagEntry, thumbnailData []byte, 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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tagCount, _, err := bp.getUint16()
|
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log.PanicIf(err)
|
|
|
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ifdEnumerateLogger.Debugf(nil, "IFD [%s] tag-count: (%d)", ii.String(), tagCount)
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|
|
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entries = make([]*IfdTagEntry, 0)
|
|
|
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var enumeratorThumbnailOffset *IfdTagEntry
|
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var enumeratorThumbnailSize *IfdTagEntry
|
|
|
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for i := 0; i < int(tagCount); i++ {
|
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ite, err := ie.parseTag(ii, i, bp)
|
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if err != nil {
|
|
if log.Is(err, ErrTagNotFound) == true || log.Is(err, ErrTagTypeNotValid) == true {
|
|
// These tags should've been fully logged in parseTag(). The
|
|
// ITE returned is nil so we can't print anything about them, now.
|
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continue
|
|
}
|
|
|
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log.Panic(err)
|
|
}
|
|
|
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err = ie.tagPostParse(ite, med)
|
|
if err == nil {
|
|
if err == ErrTagNotFound {
|
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continue
|
|
}
|
|
|
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log.PanicIf(err)
|
|
}
|
|
|
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tagId := ite.TagId()
|
|
|
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if visitor != nil {
|
|
err := visitor(ite)
|
|
log.PanicIf(err)
|
|
}
|
|
|
|
if ite.IsThumbnailOffset() == true {
|
|
ifdEnumerateLogger.Debugf(nil, "Skipping the thumbnail offset tag (0x%04x). Use accessors to get it or set it.", tagId)
|
|
|
|
enumeratorThumbnailOffset = ite
|
|
entries = append(entries, ite)
|
|
|
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continue
|
|
} else if ite.IsThumbnailSize() == true {
|
|
ifdEnumerateLogger.Debugf(nil, "Skipping the thumbnail size tag (0x%04x). Use accessors to get it or set it.", tagId)
|
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|
|
enumeratorThumbnailSize = ite
|
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entries = append(entries, ite)
|
|
|
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continue
|
|
}
|
|
|
|
if ite.TagType() != exifcommon.TypeUndefined {
|
|
// If this tag's value is an offset, bump our max-offset value to
|
|
// what that offset is plus however large that value is.
|
|
|
|
vc := ite.getValueContext()
|
|
|
|
farOffset, err := vc.GetFarOffset()
|
|
if err == nil {
|
|
candidateOffset := farOffset + uint32(vc.SizeInBytes())
|
|
if candidateOffset > ie.furthestOffset {
|
|
ie.furthestOffset = candidateOffset
|
|
}
|
|
} else if err != exifcommon.ErrNotFarValue {
|
|
log.PanicIf(err)
|
|
}
|
|
}
|
|
|
|
// If it's an IFD but not a standard one, it'll just be seen as a LONG
|
|
// (the standard IFD tag type), later, unless we skip it because it's
|
|
// [likely] not even in the standard list of known tags.
|
|
if ite.ChildIfdPath() != "" {
|
|
if doDescend == true {
|
|
ifdEnumerateLogger.Debugf(nil, "Descending from IFD [%s] to IFD [%s].", ii, ite.ChildIfdPath())
|
|
|
|
currentIfdTag := ii.IfdTag()
|
|
|
|
childIfdTag :=
|
|
exifcommon.NewIfdTag(
|
|
¤tIfdTag,
|
|
ite.TagId(),
|
|
ite.ChildIfdName())
|
|
|
|
iiChild := ii.NewChild(childIfdTag, 0)
|
|
|
|
err := ie.scan(iiChild, ite.getValueOffset(), visitor, med)
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Ascending from IFD [%s] to IFD [%s].", ite.ChildIfdPath(), ii)
|
|
}
|
|
}
|
|
|
|
entries = append(entries, ite)
|
|
}
|
|
|
|
if enumeratorThumbnailOffset != nil && enumeratorThumbnailSize != nil {
|
|
thumbnailData, err = ie.parseThumbnail(enumeratorThumbnailOffset, enumeratorThumbnailSize)
|
|
if err != nil {
|
|
ifdEnumerateLogger.Errorf(
|
|
nil, err,
|
|
"We tried to bump our furthest-offset counter but there was an issue first seeking past the thumbnail.")
|
|
} else {
|
|
// In this case, the value is always an offset.
|
|
offset := enumeratorThumbnailOffset.getValueOffset()
|
|
|
|
// This this case, the value is always a length.
|
|
length := enumeratorThumbnailSize.getValueOffset()
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Found thumbnail in IFD [%s]. Its offset is (%d) and is (%d) bytes.", ii, offset, length)
|
|
|
|
furthestOffset := offset + length
|
|
|
|
if furthestOffset > ie.furthestOffset {
|
|
ie.furthestOffset = furthestOffset
|
|
}
|
|
}
|
|
}
|
|
|
|
nextIfdOffset, _, err = bp.getUint32()
|
|
log.PanicIf(err)
|
|
|
|
_, alreadyVisited := ie.visitedIfdOffsets[nextIfdOffset]
|
|
|
|
if alreadyVisited == true {
|
|
ifdEnumerateLogger.Warningf(nil, "IFD at offset (0x%08x) has been linked-to more than once. There might be a cycle in the IFD chain. Not reparsing.", nextIfdOffset)
|
|
nextIfdOffset = 0
|
|
}
|
|
|
|
if nextIfdOffset != 0 {
|
|
ie.visitedIfdOffsets[nextIfdOffset] = struct{}{}
|
|
ifdEnumerateLogger.Debugf(nil, "[%s] Next IFD at offset: (0x%08x)", ii.String(), nextIfdOffset)
|
|
} else {
|
|
ifdEnumerateLogger.Debugf(nil, "[%s] IFD chain has terminated.", ii.String())
|
|
}
|
|
|
|
return nextIfdOffset, entries, thumbnailData, nil
|
|
}
|
|
|
|
func (ie *IfdEnumerate) parseThumbnail(offsetIte, lengthIte *IfdTagEntry) (thumbnailData []byte, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
vRaw, err := lengthIte.Value()
|
|
log.PanicIf(err)
|
|
|
|
vList := vRaw.([]uint32)
|
|
if len(vList) != 1 {
|
|
log.Panicf("not exactly one long: (%d)", len(vList))
|
|
}
|
|
|
|
length := vList[0]
|
|
|
|
// The tag is official a LONG type, but it's actually an offset to a blob of bytes.
|
|
offsetIte.updateTagType(exifcommon.TypeByte)
|
|
offsetIte.updateUnitCount(length)
|
|
|
|
thumbnailData, err = offsetIte.GetRawBytes()
|
|
log.PanicIf(err)
|
|
|
|
return thumbnailData, nil
|
|
}
|
|
|
|
// scan parses and enumerates the different IFD blocks and invokes a visitor
|
|
// callback for each tag. No information is kept or returned.
|
|
func (ie *IfdEnumerate) scan(iiGeneral *exifcommon.IfdIdentity, ifdOffset uint32, visitor TagVisitorFn, med *MiscellaneousExifData) (err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
for ifdIndex := 0; ; ifdIndex++ {
|
|
iiSibling := iiGeneral.NewSibling(ifdIndex)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Parsing IFD [%s] at offset (0x%04x) (scan).", iiSibling.String(), ifdOffset)
|
|
|
|
bp, err := ie.getByteParser(ifdOffset)
|
|
if err != nil {
|
|
if err == ErrOffsetInvalid {
|
|
ifdEnumerateLogger.Errorf(nil, nil, "IFD [%s] at offset (0x%04x) is unreachable. Terminating scan.", iiSibling.String(), ifdOffset)
|
|
break
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
|
|
nextIfdOffset, _, _, err := ie.parseIfd(iiSibling, bp, visitor, true, med)
|
|
log.PanicIf(err)
|
|
|
|
currentOffset := bp.CurrentOffset()
|
|
if currentOffset > ie.furthestOffset {
|
|
ie.furthestOffset = currentOffset
|
|
}
|
|
|
|
if nextIfdOffset == 0 {
|
|
break
|
|
}
|
|
|
|
ifdOffset = nextIfdOffset
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// MiscellaneousExifData is reports additional data collected during the parse.
|
|
type MiscellaneousExifData struct {
|
|
// UnknownTags contains all tags that were invalid for their containing
|
|
// IFDs. The values represent alternative IFDs that were correctly matched
|
|
// to those tags and used instead.
|
|
unknownTags map[exifcommon.BasicTag]exifcommon.BasicTag
|
|
}
|
|
|
|
// UnknownTags returns the unknown tags encountered during the scan.
|
|
func (med *MiscellaneousExifData) UnknownTags() map[exifcommon.BasicTag]exifcommon.BasicTag {
|
|
return med.unknownTags
|
|
}
|
|
|
|
// ScanOptions tweaks parser behavior/choices.
|
|
type ScanOptions struct {
|
|
// NOTE(dustin): Reserved for future usage.
|
|
}
|
|
|
|
// Scan enumerates the different EXIF blocks (called IFDs). `rootIfdName` will
|
|
// be "IFD" in the TIFF standard.
|
|
func (ie *IfdEnumerate) Scan(iiRoot *exifcommon.IfdIdentity, ifdOffset uint32, visitor TagVisitorFn, so *ScanOptions) (med *MiscellaneousExifData, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
med = &MiscellaneousExifData{
|
|
unknownTags: make(map[exifcommon.BasicTag]exifcommon.BasicTag),
|
|
}
|
|
|
|
err = ie.scan(iiRoot, ifdOffset, visitor, med)
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Scan: It looks like the furthest offset that contained EXIF data in the EXIF blob was (%d) (Scan).", ie.FurthestOffset())
|
|
|
|
return med, nil
|
|
}
|
|
|
|
// Ifd represents a single, parsed IFD.
|
|
type Ifd struct {
|
|
ifdIdentity *exifcommon.IfdIdentity
|
|
|
|
ifdMapping *exifcommon.IfdMapping
|
|
tagIndex *TagIndex
|
|
|
|
offset uint32
|
|
byteOrder binary.ByteOrder
|
|
id int
|
|
|
|
parentIfd *Ifd
|
|
|
|
// ParentTagIndex is our tag position in the parent IFD, if we had a parent
|
|
// (if `ParentIfd` is not nil and we weren't an IFD referenced as a sibling
|
|
// instead of as a child).
|
|
parentTagIndex int
|
|
|
|
entries []*IfdTagEntry
|
|
entriesByTagId map[uint16][]*IfdTagEntry
|
|
|
|
children []*Ifd
|
|
childIfdIndex map[string]*Ifd
|
|
|
|
thumbnailData []byte
|
|
|
|
nextIfdOffset uint32
|
|
nextIfd *Ifd
|
|
}
|
|
|
|
// IfdIdentity returns IFD identity that this struct represents.
|
|
func (ifd *Ifd) IfdIdentity() *exifcommon.IfdIdentity {
|
|
return ifd.ifdIdentity
|
|
}
|
|
|
|
// Entries returns a flat list of all tags for this IFD.
|
|
func (ifd *Ifd) Entries() []*IfdTagEntry {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.entries
|
|
}
|
|
|
|
// EntriesByTagId returns a map of all tags for this IFD.
|
|
func (ifd *Ifd) EntriesByTagId() map[uint16][]*IfdTagEntry {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.entriesByTagId
|
|
}
|
|
|
|
// Children returns a flat list of all child IFDs of this IFD.
|
|
func (ifd *Ifd) Children() []*Ifd {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.children
|
|
}
|
|
|
|
// ChildWithIfdPath returns a map of all child IFDs of this IFD.
|
|
func (ifd *Ifd) ChildIfdIndex() map[string]*Ifd {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.childIfdIndex
|
|
}
|
|
|
|
// ParentTagIndex returns the position of this IFD's tag in its parent IFD (*if*
|
|
// there is a parent).
|
|
func (ifd *Ifd) ParentTagIndex() int {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.parentTagIndex
|
|
}
|
|
|
|
// Offset returns the offset of the IFD in the stream.
|
|
func (ifd *Ifd) Offset() uint32 {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.offset
|
|
}
|
|
|
|
// Offset returns the offset of the IFD in the stream.
|
|
func (ifd *Ifd) ByteOrder() binary.ByteOrder {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.byteOrder
|
|
}
|
|
|
|
// NextIfd returns the Ifd struct for the next IFD in the chain.
|
|
func (ifd *Ifd) NextIfd() *Ifd {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ifd.nextIfd
|
|
}
|
|
|
|
// ChildWithIfdPath returns an `Ifd` struct for the given child of the current
|
|
// IFD.
|
|
func (ifd *Ifd) ChildWithIfdPath(iiChild *exifcommon.IfdIdentity) (childIfd *Ifd, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): This is a bridge while we're introducing the IFD type-system. We should be able to use the (IfdIdentity).Equals() method for this.
|
|
ifdPath := iiChild.UnindexedString()
|
|
|
|
for _, childIfd := range ifd.children {
|
|
if childIfd.ifdIdentity.UnindexedString() == ifdPath {
|
|
return childIfd, nil
|
|
}
|
|
}
|
|
|
|
log.Panic(ErrTagNotFound)
|
|
return nil, nil
|
|
}
|
|
|
|
// FindTagWithId returns a list of tags (usually just zero or one) that match
|
|
// the given tag ID. This is efficient.
|
|
func (ifd *Ifd) FindTagWithId(tagId uint16) (results []*IfdTagEntry, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
results, found := ifd.entriesByTagId[tagId]
|
|
if found != true {
|
|
log.Panic(ErrTagNotFound)
|
|
}
|
|
|
|
return results, nil
|
|
}
|
|
|
|
// FindTagWithName returns a list of tags (usually just zero or one) that match
|
|
// the given tag name. This is not efficient (though the labor is trivial).
|
|
func (ifd *Ifd) FindTagWithName(tagName string) (results []*IfdTagEntry, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
it, err := ifd.tagIndex.GetWithName(ifd.ifdIdentity, tagName)
|
|
if log.Is(err, ErrTagNotFound) == true {
|
|
log.Panic(ErrTagNotKnown)
|
|
} else if err != nil {
|
|
log.Panic(err)
|
|
}
|
|
|
|
results = make([]*IfdTagEntry, 0)
|
|
for _, ite := range ifd.entries {
|
|
if ite.TagId() == it.Id {
|
|
results = append(results, ite)
|
|
}
|
|
}
|
|
|
|
if len(results) == 0 {
|
|
log.Panic(ErrTagNotFound)
|
|
}
|
|
|
|
return results, nil
|
|
}
|
|
|
|
// String returns a description string.
|
|
func (ifd *Ifd) String() string {
|
|
parentOffset := uint32(0)
|
|
if ifd.parentIfd != nil {
|
|
parentOffset = ifd.parentIfd.offset
|
|
}
|
|
|
|
return fmt.Sprintf("Ifd<ID=(%d) IFD-PATH=[%s] INDEX=(%d) COUNT=(%d) OFF=(0x%04x) CHILDREN=(%d) PARENT=(0x%04x) NEXT-IFD=(0x%04x)>", ifd.id, ifd.ifdIdentity.UnindexedString(), ifd.ifdIdentity.Index(), len(ifd.entries), ifd.offset, len(ifd.children), parentOffset, ifd.nextIfdOffset)
|
|
}
|
|
|
|
// Thumbnail returns the raw thumbnail bytes. This is typically directly
|
|
// readable by any standard image viewer.
|
|
func (ifd *Ifd) Thumbnail() (data []byte, err error) {
|
|
|
|
if ifd.thumbnailData == nil {
|
|
return nil, ErrNoThumbnail
|
|
}
|
|
|
|
return ifd.thumbnailData, nil
|
|
}
|
|
|
|
// dumpTags recursively builds a list of tags from an IFD.
|
|
func (ifd *Ifd) dumpTags(tags []*IfdTagEntry) []*IfdTagEntry {
|
|
if tags == nil {
|
|
tags = make([]*IfdTagEntry, 0)
|
|
}
|
|
|
|
// Now, print the tags while also descending to child-IFDS as we encounter them.
|
|
|
|
ifdsFoundCount := 0
|
|
|
|
for _, ite := range ifd.entries {
|
|
tags = append(tags, ite)
|
|
|
|
childIfdPath := ite.ChildIfdPath()
|
|
if childIfdPath != "" {
|
|
ifdsFoundCount++
|
|
|
|
childIfd, found := ifd.childIfdIndex[childIfdPath]
|
|
if found != true {
|
|
log.Panicf("alien child IFD referenced by a tag: [%s]", childIfdPath)
|
|
}
|
|
|
|
tags = childIfd.dumpTags(tags)
|
|
}
|
|
}
|
|
|
|
if len(ifd.children) != ifdsFoundCount {
|
|
log.Panicf("have one or more dangling child IFDs: (%d) != (%d)", len(ifd.children), ifdsFoundCount)
|
|
}
|
|
|
|
if ifd.nextIfd != nil {
|
|
tags = ifd.nextIfd.dumpTags(tags)
|
|
}
|
|
|
|
return tags
|
|
}
|
|
|
|
// DumpTags prints the IFD hierarchy.
|
|
func (ifd *Ifd) DumpTags() []*IfdTagEntry {
|
|
return ifd.dumpTags(nil)
|
|
}
|
|
|
|
func (ifd *Ifd) printTagTree(populateValues bool, index, level int, nextLink bool) {
|
|
indent := strings.Repeat(" ", level*2)
|
|
|
|
prefix := " "
|
|
if nextLink {
|
|
prefix = ">"
|
|
}
|
|
|
|
fmt.Printf("%s%sIFD: %s\n", indent, prefix, ifd)
|
|
|
|
// Now, print the tags while also descending to child-IFDS as we encounter them.
|
|
|
|
ifdsFoundCount := 0
|
|
|
|
for _, ite := range ifd.entries {
|
|
if ite.ChildIfdPath() != "" {
|
|
fmt.Printf("%s - TAG: %s\n", indent, ite)
|
|
} else {
|
|
// This will just add noise to the output (byte-tags are fully
|
|
// dumped).
|
|
if ite.IsThumbnailOffset() == true || ite.IsThumbnailSize() == true {
|
|
continue
|
|
}
|
|
|
|
it, err := ifd.tagIndex.Get(ifd.ifdIdentity, ite.TagId())
|
|
|
|
tagName := ""
|
|
if err == nil {
|
|
tagName = it.Name
|
|
}
|
|
|
|
var valuePhrase string
|
|
if populateValues == true {
|
|
var err error
|
|
|
|
valuePhrase, err = ite.Format()
|
|
if err != nil {
|
|
if log.Is(err, exifcommon.ErrUnhandledUndefinedTypedTag) == true {
|
|
ifdEnumerateLogger.Warningf(nil, "Skipping non-standard undefined tag: [%s] (%04x)", ifd.ifdIdentity.UnindexedString(), ite.TagId())
|
|
continue
|
|
} else if err == exifundefined.ErrUnparseableValue {
|
|
ifdEnumerateLogger.Warningf(nil, "Skipping unparseable undefined tag: [%s] (%04x) [%s]", ifd.ifdIdentity.UnindexedString(), ite.TagId(), it.Name)
|
|
continue
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
} else {
|
|
valuePhrase = "!UNRESOLVED"
|
|
}
|
|
|
|
fmt.Printf("%s - TAG: %s NAME=[%s] VALUE=[%v]\n", indent, ite, tagName, valuePhrase)
|
|
}
|
|
|
|
childIfdPath := ite.ChildIfdPath()
|
|
if childIfdPath != "" {
|
|
ifdsFoundCount++
|
|
|
|
childIfd, found := ifd.childIfdIndex[childIfdPath]
|
|
if found != true {
|
|
log.Panicf("alien child IFD referenced by a tag: [%s]", childIfdPath)
|
|
}
|
|
|
|
childIfd.printTagTree(populateValues, 0, level+1, false)
|
|
}
|
|
}
|
|
|
|
if len(ifd.children) != ifdsFoundCount {
|
|
log.Panicf("have one or more dangling child IFDs: (%d) != (%d)", len(ifd.children), ifdsFoundCount)
|
|
}
|
|
|
|
if ifd.nextIfd != nil {
|
|
ifd.nextIfd.printTagTree(populateValues, index+1, level, true)
|
|
}
|
|
}
|
|
|
|
// PrintTagTree prints the IFD hierarchy.
|
|
func (ifd *Ifd) PrintTagTree(populateValues bool) {
|
|
ifd.printTagTree(populateValues, 0, 0, false)
|
|
}
|
|
|
|
func (ifd *Ifd) printIfdTree(level int, nextLink bool) {
|
|
indent := strings.Repeat(" ", level*2)
|
|
|
|
prefix := " "
|
|
if nextLink {
|
|
prefix = ">"
|
|
}
|
|
|
|
fmt.Printf("%s%s%s\n", indent, prefix, ifd)
|
|
|
|
// Now, print the tags while also descending to child-IFDS as we encounter them.
|
|
|
|
ifdsFoundCount := 0
|
|
|
|
for _, ite := range ifd.entries {
|
|
childIfdPath := ite.ChildIfdPath()
|
|
if childIfdPath != "" {
|
|
ifdsFoundCount++
|
|
|
|
childIfd, found := ifd.childIfdIndex[childIfdPath]
|
|
if found != true {
|
|
log.Panicf("alien child IFD referenced by a tag: [%s]", childIfdPath)
|
|
}
|
|
|
|
childIfd.printIfdTree(level+1, false)
|
|
}
|
|
}
|
|
|
|
if len(ifd.children) != ifdsFoundCount {
|
|
log.Panicf("have one or more dangling child IFDs: (%d) != (%d)", len(ifd.children), ifdsFoundCount)
|
|
}
|
|
|
|
if ifd.nextIfd != nil {
|
|
ifd.nextIfd.printIfdTree(level, true)
|
|
}
|
|
}
|
|
|
|
// PrintIfdTree prints the IFD hierarchy.
|
|
func (ifd *Ifd) PrintIfdTree() {
|
|
ifd.printIfdTree(0, false)
|
|
}
|
|
|
|
func (ifd *Ifd) dumpTree(tagsDump []string, level int) []string {
|
|
if tagsDump == nil {
|
|
tagsDump = make([]string, 0)
|
|
}
|
|
|
|
indent := strings.Repeat(" ", level*2)
|
|
|
|
var ifdPhrase string
|
|
if ifd.parentIfd != nil {
|
|
ifdPhrase = fmt.Sprintf("[%s]->[%s]:(%d)", ifd.parentIfd.ifdIdentity.UnindexedString(), ifd.ifdIdentity.UnindexedString(), ifd.ifdIdentity.Index())
|
|
} else {
|
|
ifdPhrase = fmt.Sprintf("[ROOT]->[%s]:(%d)", ifd.ifdIdentity.UnindexedString(), ifd.ifdIdentity.Index())
|
|
}
|
|
|
|
startBlurb := fmt.Sprintf("%s> IFD %s TOP", indent, ifdPhrase)
|
|
tagsDump = append(tagsDump, startBlurb)
|
|
|
|
ifdsFoundCount := 0
|
|
for _, ite := range ifd.entries {
|
|
tagsDump = append(tagsDump, fmt.Sprintf("%s - (0x%04x)", indent, ite.TagId()))
|
|
|
|
childIfdPath := ite.ChildIfdPath()
|
|
if childIfdPath != "" {
|
|
ifdsFoundCount++
|
|
|
|
childIfd, found := ifd.childIfdIndex[childIfdPath]
|
|
if found != true {
|
|
log.Panicf("alien child IFD referenced by a tag: [%s]", childIfdPath)
|
|
}
|
|
|
|
tagsDump = childIfd.dumpTree(tagsDump, level+1)
|
|
}
|
|
}
|
|
|
|
if len(ifd.children) != ifdsFoundCount {
|
|
log.Panicf("have one or more dangling child IFDs: (%d) != (%d)", len(ifd.children), ifdsFoundCount)
|
|
}
|
|
|
|
finishBlurb := fmt.Sprintf("%s< IFD %s BOTTOM", indent, ifdPhrase)
|
|
tagsDump = append(tagsDump, finishBlurb)
|
|
|
|
if ifd.nextIfd != nil {
|
|
siblingBlurb := fmt.Sprintf("%s* LINKING TO SIBLING IFD [%s]:(%d)", indent, ifd.nextIfd.ifdIdentity.UnindexedString(), ifd.nextIfd.ifdIdentity.Index())
|
|
tagsDump = append(tagsDump, siblingBlurb)
|
|
|
|
tagsDump = ifd.nextIfd.dumpTree(tagsDump, level)
|
|
}
|
|
|
|
return tagsDump
|
|
}
|
|
|
|
// DumpTree returns a list of strings describing the IFD hierarchy.
|
|
func (ifd *Ifd) DumpTree() []string {
|
|
return ifd.dumpTree(nil, 0)
|
|
}
|
|
|
|
// GpsInfo parses and consolidates the GPS info. This can only be called on the
|
|
// GPS IFD.
|
|
func (ifd *Ifd) GpsInfo() (gi *GpsInfo, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
gi = new(GpsInfo)
|
|
|
|
if ifd.ifdIdentity.Equals(exifcommon.IfdGpsInfoStandardIfdIdentity) == false {
|
|
log.Panicf("GPS can only be read on GPS IFD: [%s]", ifd.ifdIdentity.UnindexedString())
|
|
}
|
|
|
|
if tags, found := ifd.entriesByTagId[TagGpsVersionId]; found == false {
|
|
// We've seen this. We'll just have to default to assuming we're in a
|
|
// 2.2.0.0 format.
|
|
ifdEnumerateLogger.Warningf(nil, "No GPS version tag (0x%04x) found.", TagGpsVersionId)
|
|
} else {
|
|
versionBytes, err := tags[0].GetRawBytes()
|
|
log.PanicIf(err)
|
|
|
|
hit := false
|
|
for _, acceptedGpsVersion := range ValidGpsVersions {
|
|
if bytes.Compare(versionBytes, acceptedGpsVersion[:]) == 0 {
|
|
hit = true
|
|
break
|
|
}
|
|
}
|
|
|
|
if hit != true {
|
|
ifdEnumerateLogger.Warningf(nil, "GPS version not supported: %v", versionBytes)
|
|
log.Panic(ErrNoGpsTags)
|
|
}
|
|
}
|
|
|
|
tags, found := ifd.entriesByTagId[TagLatitudeId]
|
|
if found == false {
|
|
ifdEnumerateLogger.Warningf(nil, "latitude not found")
|
|
log.Panic(ErrNoGpsTags)
|
|
}
|
|
|
|
latitudeValue, err := tags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
// Look for whether North or South.
|
|
tags, found = ifd.entriesByTagId[TagLatitudeRefId]
|
|
if found == false {
|
|
ifdEnumerateLogger.Warningf(nil, "latitude-ref not found")
|
|
log.Panic(ErrNoGpsTags)
|
|
}
|
|
|
|
latitudeRefValue, err := tags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
tags, found = ifd.entriesByTagId[TagLongitudeId]
|
|
if found == false {
|
|
ifdEnumerateLogger.Warningf(nil, "longitude not found")
|
|
log.Panic(ErrNoGpsTags)
|
|
}
|
|
|
|
longitudeValue, err := tags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
// Look for whether West or East.
|
|
tags, found = ifd.entriesByTagId[TagLongitudeRefId]
|
|
if found == false {
|
|
ifdEnumerateLogger.Warningf(nil, "longitude-ref not found")
|
|
log.Panic(ErrNoGpsTags)
|
|
}
|
|
|
|
longitudeRefValue, err := tags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
// Parse location.
|
|
|
|
latitudeRaw := latitudeValue.([]exifcommon.Rational)
|
|
|
|
gi.Latitude, err = NewGpsDegreesFromRationals(latitudeRefValue.(string), latitudeRaw)
|
|
log.PanicIf(err)
|
|
|
|
longitudeRaw := longitudeValue.([]exifcommon.Rational)
|
|
|
|
gi.Longitude, err = NewGpsDegreesFromRationals(longitudeRefValue.(string), longitudeRaw)
|
|
log.PanicIf(err)
|
|
|
|
// Parse altitude.
|
|
|
|
altitudeTags, foundAltitude := ifd.entriesByTagId[TagAltitudeId]
|
|
altitudeRefTags, foundAltitudeRef := ifd.entriesByTagId[TagAltitudeRefId]
|
|
|
|
if foundAltitude == true && foundAltitudeRef == true {
|
|
altitudePhrase, err := altitudeTags[0].Format()
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Altitude is [%s].", altitudePhrase)
|
|
|
|
altitudeValue, err := altitudeTags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
altitudeRefPhrase, err := altitudeRefTags[0].Format()
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Altitude-reference is [%s].", altitudeRefPhrase)
|
|
|
|
altitudeRefValue, err := altitudeRefTags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
altitudeRaw := altitudeValue.([]exifcommon.Rational)
|
|
if altitudeRaw[0].Denominator > 0 {
|
|
altitude := int(altitudeRaw[0].Numerator / altitudeRaw[0].Denominator)
|
|
|
|
if altitudeRefValue.([]byte)[0] == 1 {
|
|
altitude *= -1
|
|
}
|
|
|
|
gi.Altitude = altitude
|
|
}
|
|
}
|
|
|
|
// Parse timestamp from separate date and time tags.
|
|
|
|
timestampTags, foundTimestamp := ifd.entriesByTagId[TagTimestampId]
|
|
datestampTags, foundDatestamp := ifd.entriesByTagId[TagDatestampId]
|
|
|
|
if foundTimestamp == true && foundDatestamp == true {
|
|
datestampValue, err := datestampTags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
datePhrase := datestampValue.(string)
|
|
ifdEnumerateLogger.Debugf(nil, "Date tag value is [%s].", datePhrase)
|
|
|
|
// Normalize the separators.
|
|
datePhrase = strings.ReplaceAll(datePhrase, "-", ":")
|
|
|
|
dateParts := strings.Split(datePhrase, ":")
|
|
|
|
year, err1 := strconv.ParseUint(dateParts[0], 10, 16)
|
|
month, err2 := strconv.ParseUint(dateParts[1], 10, 8)
|
|
day, err3 := strconv.ParseUint(dateParts[2], 10, 8)
|
|
|
|
if err1 == nil && err2 == nil && err3 == nil {
|
|
timestampValue, err := timestampTags[0].Value()
|
|
log.PanicIf(err)
|
|
|
|
timePhrase, err := timestampTags[0].Format()
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Time tag value is [%s].", timePhrase)
|
|
|
|
timestampRaw := timestampValue.([]exifcommon.Rational)
|
|
|
|
hour := int(timestampRaw[0].Numerator / timestampRaw[0].Denominator)
|
|
minute := int(timestampRaw[1].Numerator / timestampRaw[1].Denominator)
|
|
second := int(timestampRaw[2].Numerator / timestampRaw[2].Denominator)
|
|
|
|
gi.Timestamp = time.Date(int(year), time.Month(month), int(day), hour, minute, second, 0, time.UTC)
|
|
}
|
|
}
|
|
|
|
return gi, nil
|
|
}
|
|
|
|
// ParsedTagVisitor is a callback used if wanting to visit through all tags and
|
|
// child IFDs from the current IFD and going down.
|
|
type ParsedTagVisitor func(*Ifd, *IfdTagEntry) error
|
|
|
|
// EnumerateTagsRecursively calls the given visitor function for every tag and
|
|
// IFD in the current IFD, recursively.
|
|
func (ifd *Ifd) EnumerateTagsRecursively(visitor ParsedTagVisitor) (err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
for ptr := ifd; ptr != nil; ptr = ptr.nextIfd {
|
|
for _, ite := range ifd.entries {
|
|
childIfdPath := ite.ChildIfdPath()
|
|
if childIfdPath != "" {
|
|
childIfd := ifd.childIfdIndex[childIfdPath]
|
|
|
|
err := childIfd.EnumerateTagsRecursively(visitor)
|
|
log.PanicIf(err)
|
|
} else {
|
|
err := visitor(ifd, ite)
|
|
log.PanicIf(err)
|
|
}
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// QueuedIfd is one IFD that has been identified but yet to be processed.
|
|
type QueuedIfd struct {
|
|
IfdIdentity *exifcommon.IfdIdentity
|
|
|
|
Offset uint32
|
|
Parent *Ifd
|
|
|
|
// ParentTagIndex is our tag position in the parent IFD, if we had a parent
|
|
// (if `ParentIfd` is not nil and we weren't an IFD referenced as a sibling
|
|
// instead of as a child).
|
|
ParentTagIndex int
|
|
}
|
|
|
|
// IfdIndex collects a bunch of IFD and tag information stored in several
|
|
// different ways in order to provide convenient lookups.
|
|
type IfdIndex struct {
|
|
RootIfd *Ifd
|
|
Ifds []*Ifd
|
|
Tree map[int]*Ifd
|
|
Lookup map[string]*Ifd
|
|
}
|
|
|
|
// Collect enumerates the different EXIF blocks (called IFDs) and builds out an
|
|
// index struct for referencing all of the parsed data.
|
|
func (ie *IfdEnumerate) Collect(rootIfdOffset uint32) (index IfdIndex, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): Add MiscellaneousExifData to IfdIndex
|
|
|
|
tree := make(map[int]*Ifd)
|
|
ifds := make([]*Ifd, 0)
|
|
lookup := make(map[string]*Ifd)
|
|
|
|
queue := []QueuedIfd{
|
|
{
|
|
IfdIdentity: exifcommon.IfdStandardIfdIdentity,
|
|
Offset: rootIfdOffset,
|
|
},
|
|
}
|
|
|
|
edges := make(map[uint32]*Ifd)
|
|
|
|
for {
|
|
if len(queue) == 0 {
|
|
break
|
|
}
|
|
|
|
qi := queue[0]
|
|
ii := qi.IfdIdentity
|
|
|
|
offset := qi.Offset
|
|
parentIfd := qi.Parent
|
|
|
|
queue = queue[1:]
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Parsing IFD [%s] (%d) at offset (0x%04x) (Collect).", ii.String(), ii.Index(), offset)
|
|
|
|
bp, err := ie.getByteParser(offset)
|
|
if err != nil {
|
|
if err == ErrOffsetInvalid {
|
|
return index, err
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
|
|
// TODO(dustin): We don't need to pass the index in as a separate argument. Get from the II.
|
|
|
|
nextIfdOffset, entries, thumbnailData, err := ie.parseIfd(ii, bp, nil, false, nil)
|
|
log.PanicIf(err)
|
|
|
|
currentOffset := bp.CurrentOffset()
|
|
if currentOffset > ie.furthestOffset {
|
|
ie.furthestOffset = currentOffset
|
|
}
|
|
|
|
id := len(ifds)
|
|
|
|
entriesByTagId := make(map[uint16][]*IfdTagEntry)
|
|
for _, ite := range entries {
|
|
tagId := ite.TagId()
|
|
|
|
tags, found := entriesByTagId[tagId]
|
|
if found == false {
|
|
tags = make([]*IfdTagEntry, 0)
|
|
}
|
|
|
|
entriesByTagId[tagId] = append(tags, ite)
|
|
}
|
|
|
|
ifd := &Ifd{
|
|
ifdIdentity: ii,
|
|
|
|
byteOrder: ie.byteOrder,
|
|
|
|
id: id,
|
|
|
|
parentIfd: parentIfd,
|
|
parentTagIndex: qi.ParentTagIndex,
|
|
|
|
offset: offset,
|
|
entries: entries,
|
|
entriesByTagId: entriesByTagId,
|
|
|
|
// This is populated as each child is processed.
|
|
children: make([]*Ifd, 0),
|
|
|
|
nextIfdOffset: nextIfdOffset,
|
|
thumbnailData: thumbnailData,
|
|
|
|
ifdMapping: ie.ifdMapping,
|
|
tagIndex: ie.tagIndex,
|
|
}
|
|
|
|
// Add ourselves to a big list of IFDs.
|
|
ifds = append(ifds, ifd)
|
|
|
|
// Install ourselves into a by-id lookup table (keys are unique).
|
|
tree[id] = ifd
|
|
|
|
// Install into by-name buckets.
|
|
lookup[ii.String()] = ifd
|
|
|
|
// Add a link from the previous IFD in the chain to us.
|
|
if previousIfd, found := edges[offset]; found == true {
|
|
previousIfd.nextIfd = ifd
|
|
}
|
|
|
|
// Attach as a child to our parent (where we appeared as a tag in
|
|
// that IFD).
|
|
if parentIfd != nil {
|
|
parentIfd.children = append(parentIfd.children, ifd)
|
|
}
|
|
|
|
// Determine if any of our entries is a child IFD and queue it.
|
|
for i, ite := range entries {
|
|
if ite.ChildIfdPath() == "" {
|
|
continue
|
|
}
|
|
|
|
tagId := ite.TagId()
|
|
childIfdName := ite.ChildIfdName()
|
|
|
|
currentIfdTag := ii.IfdTag()
|
|
|
|
childIfdTag :=
|
|
exifcommon.NewIfdTag(
|
|
¤tIfdTag,
|
|
tagId,
|
|
childIfdName)
|
|
|
|
iiChild := ii.NewChild(childIfdTag, 0)
|
|
|
|
qi := QueuedIfd{
|
|
IfdIdentity: iiChild,
|
|
|
|
Offset: ite.getValueOffset(),
|
|
Parent: ifd,
|
|
ParentTagIndex: i,
|
|
}
|
|
|
|
queue = append(queue, qi)
|
|
}
|
|
|
|
// If there's another IFD in the chain.
|
|
if nextIfdOffset != 0 {
|
|
iiSibling := ii.NewSibling(ii.Index() + 1)
|
|
|
|
// Allow the next link to know what the previous link was.
|
|
edges[nextIfdOffset] = ifd
|
|
|
|
qi := QueuedIfd{
|
|
IfdIdentity: iiSibling,
|
|
Offset: nextIfdOffset,
|
|
}
|
|
|
|
queue = append(queue, qi)
|
|
}
|
|
}
|
|
|
|
index.RootIfd = tree[0]
|
|
index.Ifds = ifds
|
|
index.Tree = tree
|
|
index.Lookup = lookup
|
|
|
|
err = ie.setChildrenIndex(index.RootIfd)
|
|
log.PanicIf(err)
|
|
|
|
ifdEnumerateLogger.Debugf(nil, "Collect: It looks like the furthest offset that contained EXIF data in the EXIF blob was (%d).", ie.FurthestOffset())
|
|
|
|
return index, nil
|
|
}
|
|
|
|
func (ie *IfdEnumerate) setChildrenIndex(ifd *Ifd) (err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
childIfdIndex := make(map[string]*Ifd)
|
|
for _, childIfd := range ifd.children {
|
|
childIfdIndex[childIfd.ifdIdentity.UnindexedString()] = childIfd
|
|
}
|
|
|
|
ifd.childIfdIndex = childIfdIndex
|
|
|
|
for _, childIfd := range ifd.children {
|
|
err := ie.setChildrenIndex(childIfd)
|
|
log.PanicIf(err)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// FurthestOffset returns the furthest offset visited in the EXIF blob. This
|
|
// *does not* account for the locations of any undefined tags since we always
|
|
// evaluate the furthest offset, whether or not the user wants to know it.
|
|
//
|
|
// We are not willing to incur the cost of actually parsing those tags just to
|
|
// know their length when there are still undefined tags that are out there
|
|
// that we still won't have any idea how to parse, thus making this an
|
|
// approximation regardless of how clever we get.
|
|
func (ie *IfdEnumerate) FurthestOffset() uint32 {
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
return ie.furthestOffset
|
|
}
|
|
|
|
// parseOneIfd is a hack to use an IE to parse a raw IFD block. Can be used for
|
|
// testing. The fqIfdPath ("fully-qualified IFD path") will be less qualified
|
|
// in that the numeric index will always be zero (the zeroth child) rather than
|
|
// the proper number (if its actually a sibling to the first child, for
|
|
// instance).
|
|
func parseOneIfd(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, ii *exifcommon.IfdIdentity, byteOrder binary.ByteOrder, ifdBlock []byte, visitor TagVisitorFn) (nextIfdOffset uint32, entries []*IfdTagEntry, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
ebs := NewExifReadSeekerWithBytes(ifdBlock)
|
|
|
|
rs, err := ebs.GetReadSeeker(0)
|
|
log.PanicIf(err)
|
|
|
|
bp, err := newByteParser(rs, byteOrder, 0)
|
|
if err != nil {
|
|
if err == ErrOffsetInvalid {
|
|
return 0, nil, err
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
|
|
dummyEbs := NewExifReadSeekerWithBytes([]byte{})
|
|
ie := NewIfdEnumerate(ifdMapping, tagIndex, dummyEbs, byteOrder)
|
|
|
|
nextIfdOffset, entries, _, err = ie.parseIfd(ii, bp, visitor, true, nil)
|
|
log.PanicIf(err)
|
|
|
|
return nextIfdOffset, entries, nil
|
|
}
|
|
|
|
// parseOneTag is a hack to use an IE to parse a raw tag block.
|
|
func parseOneTag(ifdMapping *exifcommon.IfdMapping, tagIndex *TagIndex, ii *exifcommon.IfdIdentity, byteOrder binary.ByteOrder, tagBlock []byte) (ite *IfdTagEntry, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): Add test
|
|
|
|
ebs := NewExifReadSeekerWithBytes(tagBlock)
|
|
|
|
rs, err := ebs.GetReadSeeker(0)
|
|
log.PanicIf(err)
|
|
|
|
bp, err := newByteParser(rs, byteOrder, 0)
|
|
if err != nil {
|
|
if err == ErrOffsetInvalid {
|
|
return nil, err
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
|
|
dummyEbs := NewExifReadSeekerWithBytes([]byte{})
|
|
ie := NewIfdEnumerate(ifdMapping, tagIndex, dummyEbs, byteOrder)
|
|
|
|
ite, err = ie.parseTag(ii, 0, bp)
|
|
log.PanicIf(err)
|
|
|
|
err = ie.tagPostParse(ite, nil)
|
|
if err != nil {
|
|
if err == ErrTagNotFound {
|
|
return nil, err
|
|
}
|
|
|
|
log.Panic(err)
|
|
}
|
|
|
|
return ite, nil
|
|
}
|
|
|
|
// FindIfdFromRootIfd returns the given `Ifd` given the root-IFD and path of the
|
|
// desired IFD.
|
|
func FindIfdFromRootIfd(rootIfd *Ifd, ifdPath string) (ifd *Ifd, err error) {
|
|
defer func() {
|
|
if state := recover(); state != nil {
|
|
err = log.Wrap(state.(error))
|
|
}
|
|
}()
|
|
|
|
// TODO(dustin): !! Add test.
|
|
|
|
lineage, err := rootIfd.ifdMapping.ResolvePath(ifdPath)
|
|
log.PanicIf(err)
|
|
|
|
// Confirm the first IFD is our root IFD type, and then prune it because
|
|
// from then on we'll be searching down through our children.
|
|
|
|
if len(lineage) == 0 {
|
|
log.Panicf("IFD path must be non-empty.")
|
|
} else if lineage[0].Name != exifcommon.IfdStandardIfdIdentity.Name() {
|
|
log.Panicf("First IFD path item must be [%s].", exifcommon.IfdStandardIfdIdentity.Name())
|
|
}
|
|
|
|
desiredRootIndex := lineage[0].Index
|
|
lineage = lineage[1:]
|
|
|
|
// TODO(dustin): !! This is a poorly conceived fix that just doubles the work we already have to do below, which then interacts badly with the indices not being properly represented in the IFD-phrase.
|
|
// TODO(dustin): !! <-- However, we're not sure whether we shouldn't store a secondary IFD-path with the indices. Some IFDs may not necessarily restrict which IFD indices they can be a child of (only the IFD itself matters). Validation should be delegated to the caller.
|
|
thisIfd := rootIfd
|
|
for currentRootIndex := 0; currentRootIndex < desiredRootIndex; currentRootIndex++ {
|
|
if thisIfd.nextIfd == nil {
|
|
log.Panicf("Root-IFD index (%d) does not exist in the data.", currentRootIndex)
|
|
}
|
|
|
|
thisIfd = thisIfd.nextIfd
|
|
}
|
|
|
|
for _, itii := range lineage {
|
|
var hit *Ifd
|
|
for _, childIfd := range thisIfd.children {
|
|
if childIfd.ifdIdentity.TagId() == itii.TagId {
|
|
hit = childIfd
|
|
break
|
|
}
|
|
}
|
|
|
|
// If we didn't find the child, add it.
|
|
if hit == nil {
|
|
log.Panicf("IFD [%s] in [%s] not found: %s", itii.Name, ifdPath, thisIfd.children)
|
|
}
|
|
|
|
thisIfd = hit
|
|
|
|
// If we didn't find the sibling, add it.
|
|
for i := 0; i < itii.Index; i++ {
|
|
if thisIfd.nextIfd == nil {
|
|
log.Panicf("IFD [%s] does not have (%d) occurrences/siblings", thisIfd.ifdIdentity.UnindexedString(), itii.Index)
|
|
}
|
|
|
|
thisIfd = thisIfd.nextIfd
|
|
}
|
|
}
|
|
|
|
return thisIfd, nil
|
|
}
|