public override Stream Add(long offset, Stream stream)
{
var cacheStream = new GitPackMemoryCacheStream(stream);
this.cache.Add(offset, cacheStream);
return(new GitPackMemoryCacheViewStream(cacheStream));
}
public GitPackMemoryCacheViewStream(GitPackMemoryCacheStream baseStream)
{
this.baseStream = baseStream ?? throw new ArgumentNullException(nameof(baseStream));
}
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));
}