types: report when a layer is partial

Signed-off-by: Giuseppe Scrivano <[email protected]>

storage/storage_src.go

@@ -260,9 +260,10 @@ func (s *storageImageSource) LayerInfosForCopy(ctx context.Context, instanceDige
 			return nil, fmt.Errorf("uncompressed size for layer %q is unknown", layerID)
 		}
 		blobInfo := types.BlobInfo{
-			Digest:    layer.UncompressedDigest,
-			Size:      layer.UncompressedSize,
-			MediaType: uncompressedLayerType,
+			Digest:      layer.UncompressedDigest,
+			Size:        layer.UncompressedSize,
+			MediaType:   uncompressedLayerType,
+			Incremental: layer.Incremental,
 		}
 		physicalBlobInfos = append([]types.BlobInfo{blobInfo}, physicalBlobInfos...)
 		layerID = layer.Parent

types/types.go

@@ -151,6 +151,9 @@ type BlobInfo struct {
 	// TODO: To remove together with CompressionOperation in re-design to
 	// remove field out of BlobInfo.
 	CryptoOperation LayerCrypto
+	// Incremental is used to indicate that the blob was created using a partial
+	// pull, so the uncompressed digest stored is not correct and must be validated.
+	Incremental bool
 	// Before adding any fields to this struct, read the NOTE above.
 }