/// <summary>
/// Get corrent IDocumentLookup
/// </summary>
public IDocumentLookup GetLookup(Snapshot snapshot, bool utcDate)
{
var data = new DataService(snapshot);
var indexer = new IndexService(snapshot);
// define document loader
// if index are VirtualIndex - it's also lookup document
if (!(this.Index is IDocumentLookup lookup))
{
if (this.IsIndexKeyOnly)
{
lookup = new IndexLookup(indexer, this.Fields.Single());
}
else
{
lookup = new DatafileLookup(data, utcDate, this.Fields);
}
}
return(lookup);
}
/// <summary>
/// INCLUDE: Do include in result document according path expression - Works only with DocumentLookup
/// </summary>
protected async IAsyncEnumerable <BsonDocument> Include(IAsyncEnumerable <BsonDocument> source, BsonExpression path)
{
// cached services
string last = null;
Snapshot snapshot = null;
IndexService indexer = null;
DataService data = null;
CollectionIndex index = null;
IDocumentLookup lookup = null;
await foreach (var doc in source)
{
foreach (var value in path.Execute(doc, _pragmas.Collation)
.Where(x => x.IsDocument || x.IsArray)
.ToList())
{
// if value is document, convert this ref document into full document (do another query)
if (value.IsDocument)
{
await DoInclude(value.AsDocument);
}
else
{
// if value is array, do same per item
foreach (var item in value.AsArray
.Where(x => x.IsDocument)
.Select(x => x.AsDocument))
{
await DoInclude(item);
}
}
}
yield return(doc);
}
async Task DoInclude(BsonDocument value)
{
// works only if is a document
var refId = value["$id"];
var refCol = value["$ref"];
// if has no reference, just go out
if (refId.IsNull || !refCol.IsString)
{
return;
}
// do some cache re-using when is same $ref (almost always is the same $ref collection)
if (last != refCol.AsString)
{
last = refCol.AsString;
// initialize services
snapshot = await _transaction.CreateSnapshot(LockMode.Read, last, false);
indexer = new IndexService(snapshot, _pragmas.Collation);
data = new DataService(snapshot);
lookup = new DatafileLookup(data, _pragmas.UtcDate, null);
index = snapshot.CollectionPage?.PK;
}
// fill only if index and ref node exists
if (index != null)
{
var node = await indexer.Find(index, refId, false, Query.Ascending);
if (node != null)
{
// load document based on dataBlock position
var refDoc = await lookup.Load(node);
//do not remove $id
value.Remove("$ref");
// copy values from refDocument into current documet (except _id - will keep $id)
foreach (var element in refDoc.Where(x => x.Key != "_id"))
{
value[element.Key] = element.Value;
}
}
else
{
// set in ref document that was not found
value["$missing"] = true;
}
}
}
}
/// <summary>
/// INCLUDE: Do include in result document according path expression - Works only with DocumentLookup
/// </summary>
protected IEnumerable <BsonDocument> Include(IEnumerable <BsonDocument> source, BsonExpression path)
{
// cached services
string last = null;
Snapshot snapshot = null;
IndexService indexer = null;
DataService data = null;
CollectionIndex index = null;
IDocumentLookup lookup = null;
foreach (var doc in source)
{
foreach (var value in path.Execute(doc)
.Where(x => x.IsDocument)
.Select(x => x.AsDocument)
.ToList())
{
// works only if is a document
var refId = value["$id"];
var refCol = value["$ref"];
// if has no reference, just go out
if (refId.IsNull || !refCol.IsString)
{
continue;
}
// do some cache re-using when is same $ref (almost always is the same $ref collection)
if (last != refCol.AsString)
{
last = refCol.AsString;
// initialize services
snapshot = _transaction.CreateSnapshot(LockMode.Read, last, false);
indexer = new IndexService(snapshot);
data = new DataService(snapshot);
lookup = new DatafileLookup(data, _utcDate, null);
index = snapshot.CollectionPage?.PK;
}
// fill only if index and ref node exists
if (index != null)
{
var node = indexer.Find(index, refId, false, Query.Ascending);
if (node != null)
{
// load document based on dataBlock position
var refDoc = lookup.Load(node);
value.Remove("$id");
value.Remove("$ref");
refDoc.CopyTo(value);
}
}
}
yield return(doc);
}
}
