internal ProtoOwner(byte[] array, int offset, ProtoLRUCache parent, BlockIdentifier bid)
{
_array = array;
_offset = offset;
_parent = parent;
_bid = bid;
}
internal void ReturnReference(BlockIdentifier bid)
{
lock (_lock)
{
if (!_lookup.TryGetValue(bid, out var node))
{
throw new NotImplementedException();
}
node.Value.RefCount--;
if (node.Value.RefCount == 0)
{
_lruList.AddFirst(node);
}
}
}
public unsafe void ReadBlock(IntPtr buffer, BlockIdentifier bid)
{
if (!_overlappedStructs.TryDequeue(out var overLappedPointer))
{
overLappedPointer = Marshal.AllocHGlobal(Unsafe.SizeOf <OverlappedStruct>());
}
ref var overlapped = ref Unsafe.AsRef <OverlappedStruct>((void *)overLappedPointer);
overlapped.hEvent = IntPtr.Zero;
overlapped.Internal = IntPtr.Zero;
overlapped.InternalHigh = IntPtr.Zero;
overlapped.Offset = bid.BlockId * FileConsts.PageSize;
overlapped.OffsetHigh = 0;
overlapped.Pointer = IntPtr.Zero;
overlapped.FileId = bid.FileId;
overlapped.BlockId = (int)bid.BlockId;
overlapped.LevelId = bid.LevelId;
ReadFile(_fileHandle, (void *)buffer, FileConsts.PageSize, out var readBytes, overLappedPointer);
}
public async Task <IMemoryOwner <byte> > GetMemory(FileIdentifier fileId, int blockId)
{
var bid = new BlockIdentifier()
{
BlockId = (uint)blockId, FileId = (ushort)fileId.FileId, LevelId = (ushort)fileId.Level
};
LinkedListNode <ProtoBlock> node;
ProtoBlock block = null;
var lookup = _lookup;
lock (_lock)
{
if (lookup.TryGetValue(bid, out node))
{
if (node.Value.RefCount == 0)
{
_lruList.Remove(node);
}
node.Value.RefCount++;
}
else
{
if (lookup.Count < _maxBlocks)
{
var offset = _currentOffset;
_currentOffset += FileConsts.PageSize;
block = new ProtoBlock(bid, offset);
node = new LinkedListNode <ProtoBlock>(block);
lookup.Add(bid, node);
}
else
{
var lastNode = _lruList.Last;
if (lastNode == null)
{
Console.WriteLine("We ran out of space in the blockcache");
throw new NotImplementedException("We have no space at the inn, we need to figure out what we do here so we don't deadlock");
}
else
{
lookup.Remove(lastNode.Value.BlockId);
_lruList.RemoveLast();
block = new ProtoBlock(bid, lastNode.Value.Offset);
node = new LinkedListNode <ProtoBlock>(block);
lookup.Add(bid, node);
}
}
}
}
if (block != null)
{
_files[fileId].ReadBlock(IntPtr.Add(_gcHandle.AddrOfPinnedObject(), block.Offset), bid);
ProtoEventSource.Log.ReportCacheMiss();
}
else
{
ProtoEventSource.Log.ReportCacheHit();
}
await node.Value.Task;
return(new ProtoOwner(_pinnedSlab, node.Value.Offset, this, bid));
}
public ProtoBlock(BlockIdentifier id, int offset)
{
BlockId = id;
Offset = offset;
}
