public static Stream GetObject(GitPack pack, Stream stream, long offset, string objectType, GitPackObjectType packObjectType) { if (pack == null) { throw new ArgumentNullException(nameof(pack)); } if (stream == null) { throw new ArgumentNullException(nameof(stream)); } // Read the signature #if DEBUG stream.Seek(0, SeekOrigin.Begin); Span <byte> buffer = stackalloc byte[12]; stream.ReadAll(buffer); Debug.Assert(buffer.Slice(0, 4).SequenceEqual(Signature)); var versionNumber = BinaryPrimitives.ReadInt32BigEndian(buffer.Slice(4, 4)); Debug.Assert(versionNumber == 2); var numberOfObjects = BinaryPrimitives.ReadInt32BigEndian(buffer.Slice(8, 4)); #endif stream.Seek(offset, SeekOrigin.Begin); var(type, decompressedSize) = ReadObjectHeader(stream); if (type == GitPackObjectType.OBJ_OFS_DELTA) { var baseObjectRelativeOffset = ReadVariableLengthInteger(stream); var baseObjectOffset = (long)(offset - baseObjectRelativeOffset); var deltaStream = GitObjectStream.Create(stream, decompressedSize); int baseObjectlength = ReadMbsInt(deltaStream); int targetLength = ReadMbsInt(deltaStream); var baseObjectStream = pack.GetObject(baseObjectOffset, objectType); return(new GitPackDeltafiedStream(baseObjectStream, deltaStream, targetLength)); } else if (type == GitPackObjectType.OBJ_REF_DELTA) { Span <byte> baseObjectId = stackalloc byte[20]; stream.ReadAll(baseObjectId); Stream baseObject = pack.Repository.GetObjectBySha(GitObjectId.Parse(baseObjectId), objectType, seekable: true); var deltaStream = GitObjectStream.Create(stream, decompressedSize); int baseObjectlength = ReadMbsInt(deltaStream); int targetLength = ReadMbsInt(deltaStream); return(new GitPackDeltafiedStream(baseObject, deltaStream, targetLength)); } // Tips for handling deltas: https://github.com/choffmeister/gitnet/blob/4d907623d5ce2d79a8875aee82e718c12a8aad0b/src/GitNet/GitPack.cs if (type != packObjectType) { throw new GitException(); } return(GitObjectStream.Create(stream, decompressedSize)); }
public static Stream GetObject(GitPack pack, Stream stream, long offset, string objectType, GitPackObjectType packObjectType) { if (pack is null) { throw new ArgumentNullException(nameof(pack)); } if (stream is null) { throw new ArgumentNullException(nameof(stream)); } // Read the signature #if DEBUG stream.Seek(0, SeekOrigin.Begin); Span <byte> buffer = stackalloc byte[12]; stream.ReadAll(buffer); Debug.Assert(buffer.Slice(0, 4).SequenceEqual(Signature)); var versionNumber = BinaryPrimitives.ReadInt32BigEndian(buffer.Slice(4, 4)); Debug.Assert(versionNumber == 2); var numberOfObjects = BinaryPrimitives.ReadInt32BigEndian(buffer.Slice(8, 4)); #endif stream.Seek(offset, SeekOrigin.Begin); var(type, decompressedSize) = ReadObjectHeader(stream); if (type == GitPackObjectType.OBJ_OFS_DELTA) { var baseObjectRelativeOffset = ReadVariableLengthInteger(stream); long baseObjectOffset = offset - baseObjectRelativeOffset; var deltaStream = new ZLibStream(stream, decompressedSize); var baseObjectStream = pack.GetObject(baseObjectOffset, objectType); return(new GitPackDeltafiedStream(baseObjectStream, deltaStream)); } else if (type == GitPackObjectType.OBJ_REF_DELTA) { Span <byte> baseObjectId = stackalloc byte[20]; stream.ReadAll(baseObjectId); Stream baseObject = pack.GetObjectFromRepository(GitObjectId.Parse(baseObjectId), objectType) !; var seekableBaseObject = new GitPackMemoryCacheStream(baseObject); var deltaStream = new ZLibStream(stream, decompressedSize); return(new GitPackDeltafiedStream(seekableBaseObject, deltaStream)); } // Tips for handling deltas: https://github.com/choffmeister/gitnet/blob/4d907623d5ce2d79a8875aee82e718c12a8aad0b/src/GitNet/GitPack.cs if (type != packObjectType) { throw new GitException($"An object of type {objectType} could not be located at offset {offset}.") { ErrorCode = GitException.ErrorCodes.ObjectNotFound }; } return(new ZLibStream(stream, decompressedSize)); }