internal Container Resize(int newSize)
{
Debug.Assert(IsPowerOfTwo(newSize));
// Reallocate both buckets and entries and rebuild the bucket and entries from scratch.
// This serves both to scrub entries with expired keys and to put the new entries in the proper bucket.
int[] newBuckets = new int[newSize];
for (int bucketIndex = 0; bucketIndex < newSize; bucketIndex++)
{
newBuckets[bucketIndex] = -1;
}
Entry[] newEntries = new Entry[newSize];
int newEntriesIndex = 0;
// Migrate existing entries to the new table.
for (int entriesIndex = 0; entriesIndex < _entries.Length; entriesIndex++)
{
int hashCode = _entries[entriesIndex].HashCode;
DependentHandle depHnd = _entries[entriesIndex].depHnd;
if (hashCode != -1 && depHnd.IsAllocated)
{
object primary, secondary;
depHnd.GetPrimaryAndSecondary(out primary, out secondary);
if (primary != null)
{
// Entry is used and has not expired. Link it into the appropriate bucket list.
newEntries[newEntriesIndex].HashCode = hashCode;
newEntries[newEntriesIndex].depHnd = depHnd;
int bucket = hashCode & (newBuckets.Length - 1);
newEntries[newEntriesIndex].Next = newBuckets[bucket];
newBuckets[bucket] = newEntriesIndex;
newEntriesIndex++;
}
else
{
// Pretend the item was removed, so that this container's finalizer
// will clean up this dependent handle.
Volatile.Write(ref _entries[entriesIndex].HashCode, -1);
}
}
}
// Create the new container. We want to transfer the responsibility of freeing the handles from
// the old container to the new container, and also ensure that the new container isn't finalized
// while the old container may still be in use. As such, we store a reference from the old container
// to the new one, which will keep the new container alive as long as the old one is.
var newContainer = new Container(_parent, newBuckets, newEntries, newEntriesIndex);
_oldKeepAlive = newContainer; // once this is set, the old container's finalizer will not free transferred dependent handles
GC.KeepAlive(this); // ensure we don't get finalized while accessing DependentHandles.
return(newContainer);
}
