private MultidimensionalPointResult <TPoint> TryAddPoint(TDimensionValue[] coordinates, int currentDim)
{
// We need to create a new sub-element, but we need to make sure that we do not exceed max dimension count in a concurrent situation.
// To avoid locking as much as possible (it will be inevitable in some situations inside of the concurrent dictionary), we use an
// interlocked increment of the dimension count early in the process to pre-book the new element. If all creation steps do not
// complete succesfully, we will undo the increment.
// Fortunately, it is a relatively rare case:
// The increment will be successful only if the specified coordinates vector does not (yet) exist, but the max dimension limit is not yet exhaustet.
// This can occur no more than (approx.) Cm = Md1 * Md2 * ... * Mdn times, where Mdi is the max dimension limit for dimension i.
// Check if we reached the dimensions count limit. If we did, we give up. Otherwise we start tracking whether we need to undo the increment later:
if (!this.TryIncSubdimensionsCount())
{
return(new MultidimensionalPointResult <TPoint>(MultidimensionalPointResultCodes.Failure_SubdimensionsCountLimitReached, currentDim));
}
bool mustRestoreSubdimensionsCount = true;
try
{
// We are on the last level and we need to create the actual point. However, before doing that we need to check and pre-book the total
// count limit using the same pattern as the dimension values limit:
if (!_ownerCube.TryIncTotalPointsCount())
{
return(new MultidimensionalPointResult <TPoint>(MultidimensionalPointResultCodes.Failure_TotalPointsCountLimitReached, failureCoordinateIndex: -1));
}
bool mustRestoreTotalPointsCount = true;
try
{
TPoint newPoint = _ownerCube.InvokePointsFactory(coordinates);
TDimensionValue subElementKey = coordinates[currentDim];
bool couldInsert = _elements.TryAdd(subElementKey, newPoint);
// There is a race on someone calling GetOrAddVector(..) with the same coordinates. So point may or may not already be in the list.
if (couldInsert)
{
mustRestoreTotalPointsCount = false;
mustRestoreSubdimensionsCount = false;
return(new MultidimensionalPointResult <TPoint>(MultidimensionalPointResultCodes.Success_NewPointCreated, newPoint));
}
else
{
// If the point was already in the list, then that other point created by the race winner is the one we want.
TPoint existingPoint = (TPoint)_elements[subElementKey];
return(new MultidimensionalPointResult <TPoint>(MultidimensionalPointResultCodes.Success_ExistingPointRetrieved, existingPoint));
}
}
finally
{
if (mustRestoreTotalPointsCount)
{
_ownerCube.DecTotalPointsCount();
}
}
}
finally
{
if (mustRestoreSubdimensionsCount)
{
this.DecSubdimensionsCount();
}
}
}
