public void DecodeFrom(IArrayAccessor accessor)
{
for (int i = 0; i < _tableMagicBytes.Length; i++)
{
var b = accessor[EncodedLength - _tableMagicBytes.Length + i];
if( b != _tableMagicBytes[i])
throw new InvalidOperationException("Not a sstable (bad magic number)");
}
MetaIndexHandle = new BlockHandle();
IndexHandle = new BlockHandle();
var size = MetaIndexHandle.DecodeFrom(accessor, 0);
IndexHandle.DecodeFrom(accessor, size);
}
private void InitDataIterator()
{
if (_indexIterator.IsValid == false)
{
SetDataIterator(null);
return;
}
var handle = new BlockHandle();
using (var stream = _indexIterator.CreateValueStream())
{
handle.DecodeFrom(stream);
}
if (handle.Equals(_currentDataHandle) && // nothing to change
_dataIterator != null) // but we have no iterator?
return;
IIterator blockIterator = null;
try
{
blockIterator = getIterator(_readOptions, handle);
SetDataIterator(blockIterator);
}
catch (Exception)
{
if (blockIterator != null)
blockIterator.Dispose();
throw;
}
_currentDataHandle = handle;
}
public Table(StorageState storageState, FileData fileData)
{
_storageState = storageState;
try
{
_fileData = fileData;
if (_storageState.Options.MaxBlockCacheSizePerTableFile > 0)
{
_blockCache = new LruCache<BlockHandle, Block>(_storageState.Options.MaxBlockCacheSizePerTableFile);
}
if (fileData.Size < Footer.EncodedLength)
throw new CorruptedDataException("File is too short to be an sstable");
var footer = new Footer();
using (var accessor = fileData.File.CreateAccessor(fileData.Size - Footer.EncodedLength, Footer.EncodedLength))
{
footer.DecodeFrom(accessor);
}
var readOptions = new ReadOptions
{
VerifyChecksums = _storageState.Options.ParanoidChecks
};
_indexBlock = new Block(_storageState.Options, readOptions, footer.IndexHandle, fileData);
_indexBlock.IncrementUsage();
if (_storageState.Options.FilterPolicy == null)
return; // we don't need any metadata
using (var metaBlock = new Block(_storageState.Options, readOptions, footer.MetaIndexHandle, fileData))
using (var iterator = metaBlock.CreateIterator(CaseInsensitiveComparator.Default))
{
var filterName = ("filter." + _storageState.Options.FilterPolicy.Name);
iterator.Seek(filterName);
if (iterator.IsValid && CaseInsensitiveComparator.Default.Compare(filterName, iterator.Key) == 0)
{
var handle = new BlockHandle();
using (var stream = iterator.CreateValueStream())
{
handle.DecodeFrom(stream);
}
var filterAccessor = _fileData.File.CreateAccessor(handle.Position, handle.Count);
try
{
_filter = _storageState.Options.FilterPolicy.CreateFilter(filterAccessor);
}
catch (Exception)
{
if (_filter == null)
filterAccessor.Dispose();
else
_filter.Dispose();
throw;
}
}
}
}
catch (Exception)
{
Dispose();
throw;
}
}
internal Tuple<Slice, Stream> InternalGet(ReadOptions readOptions, InternalKey key)
{
using (var iterator = _indexBlock.CreateIterator(_storageState.InternalKeyComparator))
{
iterator.Seek(key.TheInternalKey);
if (iterator.IsValid == false)
return null;
var handle = new BlockHandle();
using (var stream = iterator.CreateValueStream())
{
handle.DecodeFrom(stream);
}
if (_filter != null && _filter.KeyMayMatch(handle.Position, key.UserKey) == false)
{
return null; // opptimized not found by filter, no need to read the actual block
}
using (var blockIterator = CreateBlockIterator(readOptions, handle))
{
blockIterator.Seek(key.TheInternalKey);
if (blockIterator.IsValid == false)
return null;
return Tuple.Create(blockIterator.Key, blockIterator.CreateValueStream());
}
}
}