public IEnumerable <IDictionary> Read(Query query)
{
IDictionary <ulong, double> result = null;
while (query != null)
{
var keyHash = query.Term.Key.ToString().ToHash();
var ix = GetIndex(keyHash);
if (ix != null)
{
var match = ix.ClosestMatch(query.Term.Value.ToString());
if (match.Highscore >= VectorNode.TrueAngle)
{
var docIds = _postingsReader.Read(match.PostingsOffset)
.ToDictionary(x => x, y => match.Highscore);
if (result == null)
{
result = docIds;
}
else
{
if (query.And)
{
result = (from doc in result
join x in docIds on doc.Key equals x.Key
select doc).ToDictionary(x => x.Key, y => y.Value);
}
else if (query.Not)
{
foreach (var id in docIds)
{
result.Remove(id);
}
}
else // Or
{
foreach (var id in docIds)
{
result[id.Key] = id.Value;
}
}
}
}
query = query.Next;
}
}
if (result == null)
{
return(Enumerable.Empty <IDictionary>());
}
return(ReadDocs(result));
}
public void Remove(IEnumerable <IDictionary> data, ITokenizer tokenizer)
{
var postingsWriter = new PagedPostingsWriter(PostingsStream);
foreach (var model in data)
{
var docId = (ulong)model["_docid"];
foreach (var key in model.Keys)
{
var keyStr = key.ToString();
var keyHash = keyStr.ToHash();
var fieldIndex = GetIndex(keyHash);
if (fieldIndex == null)
{
continue;
}
var val = (IComparable)model[key];
var str = val as string;
var tokens = new HashSet <string>();
if (str != null)
{
var tokenlist = tokenizer.Tokenize(str);
foreach (var token in tokenlist)
{
tokens.Add(token);
}
}
else
{
tokens.Add(val.ToString());
}
foreach (var token in tokens)
{
// 1. find node
// 2. get postings list
// 3. find docId offset
// 2. flag document as deleted
var match = fieldIndex.ClosestMatch(token);
var postings = _postingsReader.Read(match.PostingsOffset);
long offset = 0;
foreach (var posting in postings)
{
if (posting == docId)
{
postingsWriter.FlagAsDeleted(offset, docId);
break;
}
offset += PagedPostingsWriter.BLOCK_SIZE;
}
}
}
}
}