public static VersionEdit DecodeFrom(Stream stream)
{
var result = new VersionEdit();
while (true)
{
Tag tag;
try
{
tag = (Tag)stream.Read7BitEncodedInt();
}
catch (EndOfStreamException)
{
break;
}
int level;
switch (tag)
{
case Tag.Comparator:
var slice = stream.ReadLengthPrefixedSlice();
result.SetComparatorName(slice);
break;
case Tag.LogNumber:
result.SetLogNumber((ulong)stream.Read7BitEncodedLong());
break;
case Tag.PrevLogNumber:
result.SetPrevLogNumber((ulong)stream.Read7BitEncodedLong());
break;
case Tag.NextFileNumber:
result.SetNextFile((ulong)stream.Read7BitEncodedLong());
break;
case Tag.LastSequence:
result.SetLastSequence((ulong)stream.Read7BitEncodedLong());
break;
case Tag.CompactPointer:
level = stream.Read7BitEncodedInt();
var compactionPointer = stream.ReadLengthPrefixedInternalKey();
result.SetCompactionPointer(level, compactionPointer);
break;
case Tag.DeletedFile:
level = stream.Read7BitEncodedInt();
var fileNumber = (ulong)stream.Read7BitEncodedLong();
result.DeleteFile(level, fileNumber);
break;
case Tag.NewFile:
level = stream.Read7BitEncodedInt();
var fileMetadata = new FileMetadata
{
FileNumber = (ulong)stream.Read7BitEncodedLong(),
FileSize = stream.Read7BitEncodedLong(),
SmallestKey = stream.ReadLengthPrefixedInternalKey(),
LargestKey = stream.ReadLengthPrefixedInternalKey()
};
result.AddFile(level, fileMetadata);
break;
}
}
return result;
}
public void ShouldEncodeAndDecode()
{
var versionEdit = new VersionEdit();
versionEdit.SetComparatorName("testComparator");
versionEdit.SetLastSequence(10);
versionEdit.SetLogNumber(2);
versionEdit.SetNextFile(3);
versionEdit.SetPrevLogNumber(1);
versionEdit.SetLastSequence(1);
versionEdit.AddFile(0, new FileMetadata()
{
FileNumber = 0,
FileSize = 128,
LargestKey = new InternalKey("begin", Format.MaxSequenceNumber, ItemType.Value),
SmallestKey = new InternalKey("end", Format.MaxSequenceNumber, ItemType.Value),
});
versionEdit.AddFile(1, new FileMetadata()
{
FileNumber = 1,
FileSize = 128,
LargestKey = new InternalKey("begin", Format.MaxSequenceNumber, ItemType.Value),
SmallestKey = new InternalKey("end", Format.MaxSequenceNumber, ItemType.Value),
});
versionEdit.DeleteFile(0, 3);
versionEdit.DeleteFile(1, 4);
versionEdit.SetCompactionPointer(0, new InternalKey("begin", Format.MaxSequenceNumber, ItemType.Value));
versionEdit.SetCompactionPointer(1, new InternalKey("end", Format.MaxSequenceNumber, ItemType.Value));
var memoryStream = new MemoryStream();
var logWriter = new LogWriter(new InMemoryFileSystem("test"),memoryStream, new BufferPool());
versionEdit.EncodeTo(logWriter);
memoryStream.Position = 0;
var afterDecode = VersionEdit.DecodeFrom(new LogRecordStream(memoryStream, true, new BufferPool()));
Assert.Equal(versionEdit.Comparator, afterDecode.Comparator);
Assert.Equal(versionEdit.LogNumber, afterDecode.LogNumber);
Assert.Equal(versionEdit.NextFileNumber, afterDecode.NextFileNumber);
Assert.Equal(versionEdit.PrevLogNumber, afterDecode.PrevLogNumber);
Assert.Equal(versionEdit.LogNumber, afterDecode.LogNumber);
Assert.Equal(versionEdit.PrevLogNumber, afterDecode.PrevLogNumber);
Assert.Equal(versionEdit.LastSequence, afterDecode.LastSequence);
Assert.Equal(versionEdit.NewFiles[0][0].FileNumber, afterDecode.NewFiles[0][0].FileNumber);
Assert.Equal(versionEdit.NewFiles[0][0].FileSize, afterDecode.NewFiles[0][0].FileSize);
Assert.Equal(versionEdit.NewFiles[0][0].LargestKey, afterDecode.NewFiles[0][0].LargestKey);
Assert.Equal(versionEdit.NewFiles[0][0].SmallestKey, afterDecode.NewFiles[0][0].SmallestKey);
Assert.Equal(versionEdit.NewFiles[1][0].FileNumber, afterDecode.NewFiles[1][0].FileNumber);
Assert.Equal(versionEdit.NewFiles[1][0].FileSize, afterDecode.NewFiles[1][0].FileSize);
Assert.Equal(versionEdit.NewFiles[1][0].LargestKey, afterDecode.NewFiles[1][0].LargestKey);
Assert.Equal(versionEdit.NewFiles[1][0].SmallestKey, afterDecode.NewFiles[1][0].SmallestKey);
Assert.Equal(versionEdit.DeletedFiles[0][0], afterDecode.DeletedFiles[0][0]);
Assert.Equal(versionEdit.DeletedFiles[1][0], afterDecode.DeletedFiles[1][0]);
Assert.Equal(versionEdit.CompactionPointers[0][0], afterDecode.CompactionPointers[0][0]);
Assert.Equal(versionEdit.CompactionPointers[1][0], afterDecode.CompactionPointers[1][0]);
}