/// <summary> Returns sequence of bookmarks </summary>
internal override IEnumerable<Bookmark> GetBookmarksGenerator(Table table, bool doNotRewind = false)
{
// retrieve all subcursors
var allSubcursors = Subpredicates
.Select(s => s.GetBookmarksGenerator(table, true))
.ToArray();
// can we oprimize it natively?
if(allSubcursors.Count() > 0 && allSubcursors.All(t => t is INativeCursor))
{
// Optimized searching by index intersection
var cursors = allSubcursors.OfType<INativeCursor>();
try
{
return Api.IntersectIndexes(
table.Database.CurrentSession,
cursors.Select(s => s.CursorHandle).ToArray())
.Select(k => new Bookmark(k)).ToList();
}
catch(EsentNoCurrentRecordException)
{
return Enumerable.Empty<Bookmark>();
}
finally
{
foreach (var cursor in cursors.OfType<IDisposable>())
cursor.Dispose();
}
}
// can't optimize by intersection, so do intersection of all
// in memory
return allSubcursors.Aggregate((acc, left) => acc.Intersect(left)).ToList();
}
/// <summary> Before seek </summary>
internal override IEnumerable<Bookmark> GetBookmarksGenerator(Table table, bool doNotRewind)
{
var cursor = table.OpenNativeCursor(SearchIndex);
var session = cursor.Table.Database.CurrentSession;
// seek to value
var key = Converters.Convert(Val);
Api.JetMakeKey(session, cursor, key, key.Length, MakeKeyGrbit.NewKey);
Api.TrySeek(session, cursor, SeekGrbit.SeekGE);
Api.JetMakeKey(session, cursor, key, key.Length, MakeKeyGrbit.NewKey | MakeKeyGrbit.SubStrLimit);
Api.TrySetIndexRange(session, cursor, SetIndexRangeGrbit.RangeUpperLimit | SetIndexRangeGrbit.RangeInclusive);
// step back
if(!doNotRewind)
cursor.StepBack();
return cursor;
}
/// <summary> Generates bookmarks </summary> internal abstract IEnumerable<Bookmark> GetBookmarksGenerator(TTable table, bool notRewind = false);