Shorten readZstdChunkedManifest a bit further

We have the ImageSourceChunk data type, and we already construct these values, so scan into them directly instead of having three separate variables for the two bits of data. Should not change behavior. Signed-off-by: Miloslav Trmač <[email protected]>
containers · Apr 22, 2024 · ab5e270 · ab5e270
1 parent 8eeec33
commit ab5e270
Showing 1 changed file with 15 additions and 24 deletions.
diff --git a/pkg/chunked/compression_linux.go b/pkg/chunked/compression_linux.go
@@ -138,15 +138,17 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, tocDigest digest.Di
 	if offsetMetadata == "" {
 		return nil, nil, 0, fmt.Errorf("%q annotation missing", internal.ManifestInfoKey)
 	}
-	var manifestOffset, manifestLengthCompressed, manifestLengthUncompressed, manifestType uint64
-	if _, err := fmt.Sscanf(offsetMetadata, "%d:%d:%d:%d", &manifestOffset, &manifestLengthCompressed, &manifestLengthUncompressed, &manifestType); err != nil {
+	var manifestChunk ImageSourceChunk
+	var manifestLengthUncompressed, manifestType uint64
+	if _, err := fmt.Sscanf(offsetMetadata, "%d:%d:%d:%d", &manifestChunk.Offset, &manifestChunk.Length, &manifestLengthUncompressed, &manifestType); err != nil {
 		return nil, nil, 0, err
 	}
-	// The tarSplit… values are valid if tarSplitOffset > 0
-	var tarSplitOffset, tarSplitLengthCompressed, tarSplitLengthUncompressed uint64
+	// The tarSplit… values are valid if tarSplitChunk.Offset > 0
+	var tarSplitChunk ImageSourceChunk
+	var tarSplitLengthUncompressed uint64
 	var tarSplitChecksum string
 	if tarSplitInfoKeyAnnotation, found := annotations[internal.TarSplitInfoKey]; found {
-		if _, err := fmt.Sscanf(tarSplitInfoKeyAnnotation, "%d:%d:%d", &tarSplitOffset, &tarSplitLengthCompressed, &tarSplitLengthUncompressed); err != nil {
+		if _, err := fmt.Sscanf(tarSplitInfoKeyAnnotation, "%d:%d:%d", &tarSplitChunk.Offset, &tarSplitChunk.Length, &tarSplitLengthUncompressed); err != nil {
 			return nil, nil, 0, err
 		}
 		tarSplitChecksum = annotations[internal.TarSplitChecksumKey]
@@ -157,28 +159,17 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, tocDigest digest.Di
 	}
 
 	// set a reasonable limit
-	if manifestLengthCompressed > (1<<20)*50 {
+	if manifestChunk.Length > (1<<20)*50 {
 		return nil, nil, 0, errors.New("manifest too big")
 	}
 	if manifestLengthUncompressed > (1<<20)*50 {
 		return nil, nil, 0, errors.New("manifest too big")
 	}
 
-	chunk := ImageSourceChunk{
-		Offset: manifestOffset,
-		Length: manifestLengthCompressed,
-	}
-
-	chunks := []ImageSourceChunk{chunk}
-
-	if tarSplitOffset > 0 {
-		chunkTarSplit := ImageSourceChunk{
-			Offset: tarSplitOffset,
-			Length: tarSplitLengthCompressed,
-		}
-		chunks = append(chunks, chunkTarSplit)
+	chunks := []ImageSourceChunk{manifestChunk}
+	if tarSplitChunk.Offset > 0 {
+		chunks = append(chunks, tarSplitChunk)
 	}
-
 	parts, errs, err := blobStream.GetBlobAt(chunks)
 	if err != nil {
 		return nil, nil, 0, err
@@ -204,7 +195,7 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, tocDigest digest.Di
 		return blob, nil
 	}
 
-	manifest, err := readBlob(manifestLengthCompressed)
+	manifest, err := readBlob(manifestChunk.Length)
 	if err != nil {
 		return nil, nil, 0, err
 	}
@@ -214,8 +205,8 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, tocDigest digest.Di
 		return nil, nil, 0, err
 	}
 	decodedTarSplit := []byte{}
-	if tarSplitOffset > 0 {
-		tarSplit, err := readBlob(tarSplitLengthCompressed)
+	if tarSplitChunk.Offset > 0 {
+		tarSplit, err := readBlob(tarSplitChunk.Length)
 		if err != nil {
 			return nil, nil, 0, err
 		}
@@ -225,7 +216,7 @@ func readZstdChunkedManifest(blobStream ImageSourceSeekable, tocDigest digest.Di
 			return nil, nil, 0, err
 		}
 	}
-	return decodedBlob, decodedTarSplit, int64(manifestOffset), err
+	return decodedBlob, decodedTarSplit, int64(manifestChunk.Offset), err
 }
 
 func decodeAndValidateBlob(blob []byte, lengthUncompressed uint64, expectedCompressedChecksum string) ([]byte, error) {