Remove ChecksumAnntation from ZstdChunkedFooterData

Manage the value directly to simplify.

This happens to fix the ReadFooterDataFromBlob code path,
which was not setting ChecksumAnntation at all.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

pkg/chunked/compression_linux.go

@@ -145,7 +145,7 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, blobSize int64, toc
 
 	if offsetMetadata := annotations[internal.ManifestInfoKey]; offsetMetadata != "" {
 		var err error
-		footerData, err = internal.ReadFooterDataFromAnnotations(tocDigest, annotations)
+		footerData, err = internal.ReadFooterDataFromAnnotations(annotations)
 		if err != nil {
 			return nil, nil, 0, err
 		}
@@ -233,7 +233,7 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, blobSize int64, toc
 		return nil, nil, 0, err
 	}
 
-	decodedBlob, err := decodeAndValidateBlob(manifest, footerData.LengthUncompressed, footerData.ChecksumAnnotation)
+	decodedBlob, err := decodeAndValidateBlob(manifest, footerData.LengthUncompressed, tocDigest.String())
 	if err != nil {
 		return nil, nil, 0, err
 	}

pkg/chunked/internal/compression.go

@@ -183,7 +183,6 @@ func WriteZstdChunkedManifest(dest io.Writer, outMetadata map[string]string, off
 		Offset:                     manifestOffset,
 		LengthCompressed:           uint64(len(compressedManifest)),
 		LengthUncompressed:         uint64(len(manifest)),
-		ChecksumAnnotation:         "", // unused
 		OffsetTarSplit:             uint64(tarSplitOffset),
 		LengthCompressedTarSplit:   uint64(len(tarSplitData.Data)),
 		LengthUncompressedTarSplit: uint64(tarSplitData.UncompressedSize),
@@ -207,7 +206,6 @@ type ZstdChunkedFooterData struct {
 	Offset             uint64
 	LengthCompressed   uint64
 	LengthUncompressed uint64
-	ChecksumAnnotation string // Only used when reading a layer, not when creating it
 
 	OffsetTarSplit             uint64
 	LengthCompressedTarSplit   uint64
@@ -231,11 +229,9 @@ func footerDataToBlob(footer ZstdChunkedFooterData) []byte {
 }
 
 // ReadFooterDataFromAnnotations reads the zstd:chunked footer data from the given annotations.
-func ReadFooterDataFromAnnotations(tocDigest digest.Digest, annotations map[string]string) (ZstdChunkedFooterData, error) {
+func ReadFooterDataFromAnnotations(annotations map[string]string) (ZstdChunkedFooterData, error) {
 	var footerData ZstdChunkedFooterData
 
-	footerData.ChecksumAnnotation = tocDigest.String()
-
 	offsetMetadata := annotations[ManifestInfoKey]
 
 	if _, err := fmt.Sscanf(offsetMetadata, "%d:%d:%d:%d", &footerData.Offset, &footerData.LengthCompressed, &footerData.LengthUncompressed, &footerData.ManifestType); err != nil {

pkg/chunked/internal/compression_test.go

@@ -15,7 +15,6 @@ func TestGenerateAndReadFooter(t *testing.T) {
 		Offset:                     2,
 		LengthCompressed:           3,
 		LengthUncompressed:         4,
-		ChecksumAnnotation:         "", // unused
 		OffsetTarSplit:             5,
 		LengthCompressedTarSplit:   6,
 		LengthUncompressedTarSplit: 7,