public bool LoadLeafSubGrid(IStorageProxy storageProxy,
SubGridCellAddress cellAddress,
bool loadAllPasses, bool loadLatestPasses,
IServerLeafSubGrid subGrid)
{
var fullFileName = string.Empty;
var result = false;
try
{
// Loading contents into a dirty sub grid (which should happen only on the mutable nodes), or
// when there is already content in the segment directory are strictly forbidden and break immutability
// rules for sub grids
if (subGrid.Dirty)
{
throw new TRexSubGridIOException("Leaf sub grid directory loads may not be performed while the sub grid is dirty. The information should be taken from the cache instead.");
}
// Load the cells into it from its file
// Briefly lock this sub grid just for the period required to read its contents
lock (subGrid)
{
// If more than thread wants this sub grid then they may concurrently attempt to load it.
// Make a check to see if this has happened and another thread has already loaded this sub grid directory.
// If so, just return success. Previously the commented out assert was enforced causing exceptions
// Debug.Assert(SubGrid.Directory?.SegmentDirectory?.Count == 0, "Loading a leaf sub grid directory when there are already segments present within it.");
// Check this thread is the winner of the lock to be able to load the contents
if (subGrid.Directory?.SegmentDirectory?.Count == 0)
{
// Ensure the appropriate storage is allocated
if (loadAllPasses)
{
subGrid.AllocateLeafFullPassStacks();
}
if (loadLatestPasses)
{
subGrid.AllocateLeafLatestPassGrid();
}
fullFileName = GetLeafSubGridFullFileName(cellAddress);
// Briefly lock this sub grid just for the period required to read its contents
result = subGrid.LoadDirectoryFromFile(storageProxy, fullFileName);
}
else
{
// A previous thread has already read the directory so there is nothing more to do, return a true result.
return(true);
}
}
}
finally
{
if (result && RecordSubGridFileReadingToLog)
{
_log.LogDebug($"Sub grid file {fullFileName} read from persistent store containing {subGrid.Directory.SegmentDirectory.Count} segments (Moniker: {subGrid.Moniker()}");
}
}
return(result);
}