| package eu.mulk.jgvariant.ostree; |
| |
| import eu.mulk.jgvariant.core.Decoder; |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.UncheckedIOException; |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| import java.util.ArrayList; |
| import java.util.List; |
| import org.tukaani.xz.XZInputStream; |
| |
| /** |
| * A payload file from a static delta. |
| * |
| * <p>The first byte is a compression byte: {@code 0} for none, {@code 'x'} for LZMA. The actual |
| * GVariant data begins right after. |
| * |
| * <p>Reference: {@code |
| * ostree-repo-static-delta-private.h#OSTREE_STATIC_DELTA_PART_PAYLOAD_FORMAT_V0} |
| * |
| * @param fileModes the {@link FileMode}s of the files generated by this delta payload. |
| * @param xattrs the {@link Xattr}s of the files generated by this delta payload. |
| * @param rawDataSource the data bytes used in the delta operations. |
| * @param operations the operations to apply during delta patching. |
| * @see DeltaSuperblock |
| */ |
| public record DeltaPartPayload( |
| List<FileMode> fileModes, |
| List<List<Xattr>> xattrs, |
| ByteString rawDataSource, |
| List<DeltaOperation> operations) { |
| |
| private static ByteBuffer preparse(ByteBuffer byteBuffer) { |
| byte compressionByte = byteBuffer.get(0); |
| var dataSlice = byteBuffer.slice(1, byteBuffer.limit() - 1); |
| return switch (compressionByte) { |
| case 0 -> dataSlice; |
| case (byte) 'x' -> { |
| try { |
| var dataBytes = new byte[dataSlice.limit()]; |
| dataSlice.get(dataBytes); |
| var decompressingInputStream = new XZInputStream(new ByteArrayInputStream(dataBytes)); |
| |
| var decompressedOutputStream = new ByteArrayOutputStream(); |
| decompressingInputStream.transferTo(decompressedOutputStream); |
| |
| yield ByteBuffer.wrap(decompressedOutputStream.toByteArray()); |
| } catch (IOException e) { |
| // impossible |
| throw new UncheckedIOException(e); |
| } |
| } |
| default -> throw new IllegalArgumentException( |
| "unrecognized compression byte '%d'".formatted(compressionByte)); |
| }; |
| } |
| |
| private static List<DeltaOperation> parseDeltaOperationList( |
| ByteString byteString, List<ObjectType> objectTypes) { |
| List<DeltaOperation> deltaOperations = new ArrayList<>(); |
| var byteBuffer = ByteBuffer.wrap(byteString.bytes()); |
| int objectIndex = 0; |
| |
| while (byteBuffer.hasRemaining()) { |
| var currentOperation = DeltaOperation.readFrom(byteBuffer, objectTypes.get(objectIndex)); |
| deltaOperations.add(currentOperation); |
| if (currentOperation instanceof DeltaOperation.Close |
| || currentOperation instanceof DeltaOperation.OpenSpliceAndCloseMeta |
| || currentOperation instanceof DeltaOperation.OpenSpliceAndCloseReal) { |
| ++objectIndex; |
| } |
| } |
| |
| return deltaOperations; |
| } |
| |
| /** |
| * A file mode triple (UID, GID, and permission bits). |
| * |
| * @param uid the user ID that owns the file. |
| * @param gid the group ID that owns the file. |
| * @param mode the POSIX permission bits. |
| */ |
| public record FileMode(int uid, int gid, int mode) { |
| |
| private static final Decoder<FileMode> DECODER = |
| Decoder.ofStructure( |
| FileMode.class, |
| Decoder.ofInt().withByteOrder(ByteOrder.BIG_ENDIAN), |
| Decoder.ofInt().withByteOrder(ByteOrder.BIG_ENDIAN), |
| Decoder.ofInt().withByteOrder(ByteOrder.BIG_ENDIAN)); |
| |
| /** |
| * Acquires a {@link Decoder} for the enclosing type. |
| * |
| * @return a possibly shared {@link Decoder}. |
| */ |
| public static Decoder<FileMode> decoder() { |
| return DECODER; |
| } |
| } |
| |
| /** |
| * Acquires a {@link Decoder} for the enclosing type. |
| * |
| * @return a possibly shared {@link Decoder}. |
| */ |
| public static Decoder<DeltaPartPayload> decoder(DeltaMetaEntry deltaMetaEntry) { |
| var objectTypes = |
| deltaMetaEntry.objects().stream().map(DeltaMetaEntry.DeltaObject::objectType).toList(); |
| return Decoder.ofStructure( |
| DeltaPartPayload.class, |
| Decoder.ofArray(FileMode.decoder()), |
| Decoder.ofArray(Decoder.ofArray(Xattr.decoder())), |
| ByteString.decoder(), |
| ByteString.decoder() |
| .map(byteString -> parseDeltaOperationList(byteString, objectTypes))) |
| .contramap(DeltaPartPayload::preparse); |
| } |
| } |